Номер 709, страница 179 - гдз по геометрии 10-11 класс учебник Атанасян, Бутузов

Геометрия, 10-11 класс Учебник, авторы: Атанасян Левон Сергеевич, Бутузов Валентин Фёдорович, Кадомцев Сергей Борисович, Позняк Эдуард Генрихович, Киселёва Людмила Сергеевна, издательство Просвещение, Москва, 2019, коричневого цвета

Авторы: Атанасян Л. С., Бутузов В. Ф., Кадомцев С. Б., Позняк Э. Г., Киселёва Л. С.

Тип: Учебник

Издательство: Просвещение

Год издания: 2019 - 2026

Уровень обучения: базовый и углублённый

Цвет обложки: коричневый с ромбами

ISBN: 978-5-09-103606-0 (2023)

Допущено Министерством просвещения Российской Федерации

Математика: алгебра и начала математического анализа, геометрия

Глава 7. Метод координат в пространстве. Движения. Параграф 2. Скалярное произведение векторов - номер 709, страница 179.

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              #items: []
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 744405
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Метод координат в пространстве. Движения"
            "field_branch_order" => "7"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1080}
            "field_page_start" => "160"
            "field_branch_display" => "0"
            "field_branch_expanded" => "0"
            "field_display_branch_in_title" => "1"
            "field_display_task_interval" => "0"
            "field_display_branch_page" => "1"
            "field_branch_title_in_content" => "0"
            "field_navigation_title" => null
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1081}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1117}
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        1 => App\Models\Branch {#1118
          #connection: "mysql"
          #table: "branches"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:24 [
            "id" => 744407
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Скалярное произведение векторов"
            "field_branch_order" => "2"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1119
              #items: array:1 [
                0 => App\Models\Term {#1120
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:7 [ …7]
                  #original: array:7 [ …7]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "171"
            "field_branch_display" => "0"
            "field_branch_expanded" => "0"
            "field_display_branch_in_title" => "1"
            "field_display_task_interval" => "0"
            "field_display_branch_page" => "1"
            "field_branch_title_in_content" => "0"
            "field_navigation_title" => null
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1121
              #items: array:1 [
                0 => App\Models\Book {#1122
                  #connection: "mysql"
                  #table: "books"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:50 [ …50]
                  #original: array:50 [ …50]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1157
              #items: array:1 [
                0 => App\Models\Branch {#1158
                  #connection: "mysql"
                  #table: "branches"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:24 [ …24]
                  #original: array:24 [ …24]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 744407
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Скалярное произведение векторов"
            "field_branch_order" => "2"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1119}
            "field_page_start" => "171"
            "field_branch_display" => "0"
            "field_branch_expanded" => "0"
            "field_display_branch_in_title" => "1"
            "field_display_task_interval" => "0"
            "field_display_branch_page" => "1"
            "field_branch_title_in_content" => "0"
            "field_navigation_title" => null
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "field_branch_cover" => []
            "field_branch_covers" => []
            "book" => Illuminate\Database\Eloquent\Collection {#1121}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1157}
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
      ]
      #escapeWhenCastingToString: false
    }
    "content" => Illuminate\Database\Eloquent\Collection {#1164
      #items: array:6 [
        0 => App\Models\Element {#1178
          #connection: "mysql"
          #table: "elements"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:7 [
            "id" => 939601
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1187
              #items: array:1 [
                0 => App\Models\Edition {#1179
                  #connection: "mysql"
                  #table: "editions"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:21 [ …21]
                  #original: array:21 [ …21]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "task" => array:2 [
              "refs" => "745124"
              "type" => "task"
            ]
            "text" => "<p> <b>709.</b> В прямоугольном параллелепипеде <i>ABCDA₁B₁C₁D₁</i> <span class="long">AB = 1,</span> <span class="long">ВС = 2,</span> <span class="long">ВВ₁ = 3.</span> Вычислите косинус угла между прямыми: <span class="long">а) АС и D₁B;</span> <span class="long">б) AB₁ и ВС₁;</span> <span class="long">в) A₁D и АС₁.</span> </p>"
            "img" => array:1 [
              0 => array:5 [
                "name" => "709-1.jpg"
                "alt" => null
                "width" => "1562"
                "height" => 204
                "path" => "/media/geometrija_10/atanasjan-u23/0-00/709-1.webp?ts=1739436846"
              ]
            ]
          ]
          #original: array:7 [
            "id" => 939601
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1187}
            "task" => array:2 [
              "refs" => "745124"
              "type" => "task"
            ]
            "text" => "<p> <b>709.</b> В прямоугольном параллелепипеде <i>ABCDA₁B₁C₁D₁</i> <span class="long">AB = 1,</span> <span class="long">ВС = 2,</span> <span class="long">ВВ₁ = 3.</span> Вычислите косинус угла между прямыми: <span class="long">а) АС и D₁B;</span> <span class="long">б) AB₁ и ВС₁;</span> <span class="long">в) A₁D и АС₁.</span> </p>"
            "img" => array:1 [
              0 => array:5 [
                "name" => "709-1.jpg"
                "alt" => null
                "width" => "1562"
                "height" => 204
                "path" => "/media/geometrija_10/atanasjan-u23/0-00/709-1.webp?ts=1739436846"
              ]
            ]
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        1 => App\Models\Element {#1209
          #connection: "mysql"
          #table: "elements"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:6 [
            "id" => 942574
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1219
              #items: array:1 [
                0 => App\Models\Edition {#1210
                  #connection: "mysql"
                  #table: "editions"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:21 [ …21]
                  #original: array:21 [ …21]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "task" => array:2 [
              "refs" => "745124"
              "type" => "task"
            ]
            "img" => array:2 [
              0 => array:5 [
                "name" => "709-1.png"
                "alt" => null
                "width" => "694"
                "height" => 3326
                "path" => "/media/geometrija_10/atanasjan-u23/2-00/709-1.webp?ts=1739441614"
              ]
              1 => array:5 [
                "name" => "709-2.png"
                "alt" => null
                "width" => "694"
                "height" => 3324
                "path" => "/media/geometrija_10/atanasjan-u23/2-00/709-2.webp?ts=1739441614"
              ]
            ]
          ]
          #original: array:6 [
            "id" => 942574
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1219}
            "task" => array:2 [
              "refs" => "745124"
              "type" => "task"
            ]
            "img" => array:2 [
              0 => array:5 [
                "name" => "709-1.png"
                "alt" => null
                "width" => "694"
                "height" => 3326
                "path" => "/media/geometrija_10/atanasjan-u23/2-00/709-1.webp?ts=1739441614"
              ]
              1 => array:5 [
                "name" => "709-2.png"
                "alt" => null
                "width" => "694"
                "height" => 3324
                "path" => "/media/geometrija_10/atanasjan-u23/2-00/709-2.webp?ts=1739441614"
              ]
            ]
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        2 => App\Models\Element {#1201
          #connection: "mysql"
          #table: "elements"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:6 [
            "id" => 942394
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1211
              #items: array:1 [
                0 => App\Models\Edition {#1202
                  #connection: "mysql"
                  #table: "editions"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:21 [ …21]
                  #original: array:21 [ …21]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "task" => array:2 [
              "refs" => "745124"
              "type" => "task"
            ]
            "img" => array:2 [
              0 => array:5 [
                "name" => "709-1.jpg"
                "alt" => null
                "width" => "1373"
                "height" => 390
                "path" => "/media/geometrija_10/atanasjan-u23/3-00/709-1.webp?ts=1739437171"
              ]
              1 => array:5 [
                "name" => "709-2.jpg"
                "alt" => null
                "width" => "1373"
                "height" => 436
                "path" => "/media/geometrija_10/atanasjan-u23/3-00/709-2.webp?ts=1739437171"
              ]
            ]
          ]
          #original: array:6 [
            "id" => 942394
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1211}
            "task" => array:2 [
              "refs" => "745124"
              "type" => "task"
            ]
            "img" => array:2 [
              0 => array:5 [
                "name" => "709-1.jpg"
                "alt" => null
                "width" => "1373"
                "height" => 390
                "path" => "/media/geometrija_10/atanasjan-u23/3-00/709-1.webp?ts=1739437171"
              ]
              1 => array:5 [
                "name" => "709-2.jpg"
                "alt" => null
                "width" => "1373"
                "height" => 436
                "path" => "/media/geometrija_10/atanasjan-u23/3-00/709-2.webp?ts=1739437171"
              ]
            ]
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        3 => App\Models\Element {#1185
          #connection: "mysql"
          #table: "elements"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:6 [
            "id" => 941963
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1195
              #items: array:1 [
                0 => App\Models\Edition {#1186
                  #connection: "mysql"
                  #table: "editions"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:21 [ …21]
                  #original: array:21 [ …21]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "task" => array:2 [
              "refs" => "745124"
              "type" => "task"
            ]
            "img" => array:1 [
              0 => array:5 [
                "name" => "709-1.jpg"
                "alt" => null
                "width" => "1423"
                "height" => 1242
                "path" => "/media/geometrija_10/atanasjan-u23/4-00/709-1.webp?ts=1739436713"
              ]
            ]
          ]
          #original: array:6 [
            "id" => 941963
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1195}
            "task" => array:2 [
              "refs" => "745124"
              "type" => "task"
            ]
            "img" => array:1 [
              0 => array:5 [
                "name" => "709-1.jpg"
                "alt" => null
                "width" => "1423"
                "height" => 1242
                "path" => "/media/geometrija_10/atanasjan-u23/4-00/709-1.webp?ts=1739436713"
              ]
            ]
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        4 => App\Models\Element {#1193
          #connection: "mysql"
          #table: "elements"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:6 [
            "id" => 942032
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1203
              #items: array:1 [
                0 => App\Models\Edition {#1194
                  #connection: "mysql"
                  #table: "editions"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:21 [ …21]
                  #original: array:21 [ …21]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "task" => array:2 [
              "refs" => "745124"
              "type" => "task"
            ]
            "img" => array:1 [
              0 => array:5 [
                "name" => "709-1.jpg"
                "alt" => null
                "width" => "1329"
                "height" => 907
                "path" => "/media/geometrija_10/atanasjan-u23/5-00/709-1.webp?ts=1739436747"
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            "edition" => Illuminate\Database\Eloquent\Collection {#1203}
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            "created_at" => "2026-04-10 13:58:26"
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            "edition" => Illuminate\Database\Eloquent\Collection {#1227
              #items: array:1 [
                0 => App\Models\Edition {#1218
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            "text" => "<p>Для решения задачи воспользуемся координатным методом. Введем прямоугольную систему координат с началом в точке $A(0, 0, 0)$. Направим ось $Ox$ вдоль ребра $AB$, ось $Oy$ вдоль ребра $AD$ и ось $Oz$ вдоль ребра $AA_1$.</p><p>В этой системе координат, с учетом длин ребер $AB=1$, $BC=AD=2$ и $BB_1=AA_1=3$, вершины параллелепипеда будут иметь следующие координаты:</p><ul><li>$A(0, 0, 0)$</li> <li>$B(1, 0, 0)$</li> <li>$C(1, 2, 0)$</li> <li>$D(0, 2, 0)$</li> <li>$A_1(0, 0, 3)$</li> <li>$B_1(1, 0, 3)$</li> <li>$C_1(1, 2, 3)$</li> <li>$D_1(0, 2, 3)$</li></ul><p>Косинус угла $\alpha$ между двумя прямыми, заданными направляющими векторами $\vec{a}$ и $\vec{b}$, вычисляется по формуле скалярного произведения векторов:</p><p>$cos(\alpha) = \frac{|\vec{a} \cdot \vec{b}|}{|\vec{a}| \cdot |\vec{b}|}$</p><p><strong>а) AC и D?B</strong></p><p>Найдем координаты направляющих векторов для прямых $AC$ и $D_1B$.</p><p>Вектор $\vec{AC}$ имеет координаты: $\vec{AC} = \{C_x - A_x; C_y - A_y; C_z - A_z\} = \{1-0; 2-0; 0-0\} = \{1; 2; 0\}$.</p><p>Вектор $\vec{D_1B}$ имеет координаты: $\vec{D_1B} = \{B_x - D_{1x}; B_y - D_{1y}; B_z - D_{1z}\} = \{1-0; 0-2; 0-3\} = \{1; -2; -3\}$.</p><p>Вычислим скалярное произведение векторов:</p><p>$\vec{AC} \cdot \vec{D_1B} = 1 \cdot 1 + 2 \cdot (-2) + 0 \cdot (-3) = 1 - 4 + 0 = -3$.</p><p>Найдем длины (модули) векторов:</p><p>$|\vec{AC}| = \sqrt{1^2 + 2^2 + 0^2} = \sqrt{1 + 4 + 0} = \sqrt{5}$.</p><p>$|\vec{D_1B}| = \sqrt{1^2 + (-2)^2 + (-3)^2} = \sqrt{1 + 4 + 9} = \sqrt{14}$.</p><p>Теперь вычислим косинус угла $\alpha$ между прямыми:</p><p>$cos(\alpha) = \frac{|\vec{AC} \cdot \vec{D_1B}|}{|\vec{AC}| \cdot |\vec{D_1B}|} = \frac{|-3|}{\sqrt{5} \cdot \sqrt{14}} = \frac{3}{\sqrt{70}}$.</p><p>Ответ: $\frac{3}{\sqrt{70}}$.</p><p><strong>б) AB? и BC?</strong></p><p>Найдем координаты направляющих векторов для прямых $AB_1$ и $BC_1$.</p><p>Вектор $\vec{AB_1}$: $\vec{AB_1} = \{B_{1x} - A_x; B_{1y} - A_y; B_{1z} - A_z\} = \{1-0; 0-0; 3-0\} = \{1; 0; 3\}$.</p><p>Вектор $\vec{BC_1}$: $\vec{BC_1} = \{C_{1x} - B_x; C_{1y} - B_y; C_{1z} - B_z\} = \{1-1; 2-0; 3-0\} = \{0; 2; 3\}$.</p><p>Вычислим скалярное произведение векторов:</p><p>$\vec{AB_1} \cdot \vec{BC_1} = 1 \cdot 0 + 0 \cdot 2 + 3 \cdot 3 = 0 + 0 + 9 = 9$.</p><p>Найдем длины векторов:</p><p>$|\vec{AB_1}| = \sqrt{1^2 + 0^2 + 3^2} = \sqrt{1 + 9} = \sqrt{10}$.</p><p>$|\vec{BC_1}| = \sqrt{0^2 + 2^2 + 3^2} = \sqrt{4 + 9} = \sqrt{13}$.</p><p>Вычислим косинус угла $\beta$ между прямыми:</p><p>$cos(\beta) = \frac{|\vec{AB_1} \cdot \vec{BC_1}|}{|\vec{AB_1}| \cdot |\vec{BC_1}|} = \frac{|9|}{\sqrt{10} \cdot \sqrt{13}} = \frac{9}{\sqrt{130}}$.</p><p>Ответ: $\frac{9}{\sqrt{130}}$.</p><p><strong>в) A?D и AC?</strong></p><p>Найдем координаты направляющих векторов для прямых $A_1D$ и $AC_1$.</p><p>Вектор $\vec{A_1D}$: $\vec{A_1D} = \{D_x - A_{1x}; D_y - A_{1y}; D_z - A_{1z}\} = \{0-0; 2-0; 0-3\} = \{0; 2; -3\}$.</p><p>Вектор $\vec{AC_1}$: $\vec{AC_1} = \{C_{1x} - A_x; C_{1y} - A_y; C_{1z} - A_z\} = \{1-0; 2-0; 3-0\} = \{1; 2; 3\}$.</p><p>Вычислим скалярное произведение векторов:</p><p>$\vec{A_1D} \cdot \vec{AC_1} = 0 \cdot 1 + 2 \cdot 2 + (-3) \cdot 3 = 0 + 4 - 9 = -5$.</p><p>Найдем длины векторов:</p><p>$|\vec{A_1D}| = \sqrt{0^2 + 2^2 + (-3)^2} = \sqrt{4 + 9} = \sqrt{13}$.</p><p>$|\vec{AC_1}| = \sqrt{1^2 + 2^2 + 3^2} = \sqrt{1 + 4 + 9} = \sqrt{14}$.</p><p>Вычислим косинус угла $\gamma$ между прямыми:</p><p>$cos(\gamma) = \frac{|\vec{A_1D} \cdot \vec{AC_1}|}{|\vec{A_1D}| \cdot |\vec{AC_1}|} = \frac{|-5|}{\sqrt{13} \cdot \sqrt{14}} = \frac{5}{\sqrt{182}}$.</p><p>Ответ: $\frac{5}{\sqrt{182}}$.</p>"
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            "id" => 1352437
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            "text" => "<p>Для решения задачи воспользуемся координатным методом. Введем прямоугольную систему координат с началом в точке $A(0, 0, 0)$. Направим ось $Ox$ вдоль ребра $AB$, ось $Oy$ вдоль ребра $AD$ и ось $Oz$ вдоль ребра $AA_1$.</p><p>В этой системе координат, с учетом длин ребер $AB=1$, $BC=AD=2$ и $BB_1=AA_1=3$, вершины параллелепипеда будут иметь следующие координаты:</p><ul><li>$A(0, 0, 0)$</li> <li>$B(1, 0, 0)$</li> <li>$C(1, 2, 0)$</li> <li>$D(0, 2, 0)$</li> <li>$A_1(0, 0, 3)$</li> <li>$B_1(1, 0, 3)$</li> <li>$C_1(1, 2, 3)$</li> <li>$D_1(0, 2, 3)$</li></ul><p>Косинус угла $\alpha$ между двумя прямыми, заданными направляющими векторами $\vec{a}$ и $\vec{b}$, вычисляется по формуле скалярного произведения векторов:</p><p>$cos(\alpha) = \frac{|\vec{a} \cdot \vec{b}|}{|\vec{a}| \cdot |\vec{b}|}$</p><p><strong>а) AC и D?B</strong></p><p>Найдем координаты направляющих векторов для прямых $AC$ и $D_1B$.</p><p>Вектор $\vec{AC}$ имеет координаты: $\vec{AC} = \{C_x - A_x; C_y - A_y; C_z - A_z\} = \{1-0; 2-0; 0-0\} = \{1; 2; 0\}$.</p><p>Вектор $\vec{D_1B}$ имеет координаты: $\vec{D_1B} = \{B_x - D_{1x}; B_y - D_{1y}; B_z - D_{1z}\} = \{1-0; 0-2; 0-3\} = \{1; -2; -3\}$.</p><p>Вычислим скалярное произведение векторов:</p><p>$\vec{AC} \cdot \vec{D_1B} = 1 \cdot 1 + 2 \cdot (-2) + 0 \cdot (-3) = 1 - 4 + 0 = -3$.</p><p>Найдем длины (модули) векторов:</p><p>$|\vec{AC}| = \sqrt{1^2 + 2^2 + 0^2} = \sqrt{1 + 4 + 0} = \sqrt{5}$.</p><p>$|\vec{D_1B}| = \sqrt{1^2 + (-2)^2 + (-3)^2} = \sqrt{1 + 4 + 9} = \sqrt{14}$.</p><p>Теперь вычислим косинус угла $\alpha$ между прямыми:</p><p>$cos(\alpha) = \frac{|\vec{AC} \cdot \vec{D_1B}|}{|\vec{AC}| \cdot |\vec{D_1B}|} = \frac{|-3|}{\sqrt{5} \cdot \sqrt{14}} = \frac{3}{\sqrt{70}}$.</p><p>Ответ: $\frac{3}{\sqrt{70}}$.</p><p><strong>б) AB? и BC?</strong></p><p>Найдем координаты направляющих векторов для прямых $AB_1$ и $BC_1$.</p><p>Вектор $\vec{AB_1}$: $\vec{AB_1} = \{B_{1x} - A_x; B_{1y} - A_y; B_{1z} - A_z\} = \{1-0; 0-0; 3-0\} = \{1; 0; 3\}$.</p><p>Вектор $\vec{BC_1}$: $\vec{BC_1} = \{C_{1x} - B_x; C_{1y} - B_y; C_{1z} - B_z\} = \{1-1; 2-0; 3-0\} = \{0; 2; 3\}$.</p><p>Вычислим скалярное произведение векторов:</p><p>$\vec{AB_1} \cdot \vec{BC_1} = 1 \cdot 0 + 0 \cdot 2 + 3 \cdot 3 = 0 + 0 + 9 = 9$.</p><p>Найдем длины векторов:</p><p>$|\vec{AB_1}| = \sqrt{1^2 + 0^2 + 3^2} = \sqrt{1 + 9} = \sqrt{10}$.</p><p>$|\vec{BC_1}| = \sqrt{0^2 + 2^2 + 3^2} = \sqrt{4 + 9} = \sqrt{13}$.</p><p>Вычислим косинус угла $\beta$ между прямыми:</p><p>$cos(\beta) = \frac{|\vec{AB_1} \cdot \vec{BC_1}|}{|\vec{AB_1}| \cdot |\vec{BC_1}|} = \frac{|9|}{\sqrt{10} \cdot \sqrt{13}} = \frac{9}{\sqrt{130}}$.</p><p>Ответ: $\frac{9}{\sqrt{130}}$.</p><p><strong>в) A?D и AC?</strong></p><p>Найдем координаты направляющих векторов для прямых $A_1D$ и $AC_1$.</p><p>Вектор $\vec{A_1D}$: $\vec{A_1D} = \{D_x - A_{1x}; D_y - A_{1y}; D_z - A_{1z}\} = \{0-0; 2-0; 0-3\} = \{0; 2; -3\}$.</p><p>Вектор $\vec{AC_1}$: $\vec{AC_1} = \{C_{1x} - A_x; C_{1y} - A_y; C_{1z} - A_z\} = \{1-0; 2-0; 3-0\} = \{1; 2; 3\}$.</p><p>Вычислим скалярное произведение векторов:</p><p>$\vec{A_1D} \cdot \vec{AC_1} = 0 \cdot 1 + 2 \cdot 2 + (-3) \cdot 3 = 0 + 4 - 9 = -5$.</p><p>Найдем длины векторов:</p><p>$|\vec{A_1D}| = \sqrt{0^2 + 2^2 + (-3)^2} = \sqrt{4 + 9} = \sqrt{13}$.</p><p>$|\vec{AC_1}| = \sqrt{1^2 + 2^2 + 3^2} = \sqrt{1 + 4 + 9} = \sqrt{14}$.</p><p>Вычислим косинус угла $\gamma$ между прямыми:</p><p>$cos(\gamma) = \frac{|\vec{A_1D} \cdot \vec{AC_1}|}{|\vec{A_1D}| \cdot |\vec{AC_1}|} = \frac{|-5|}{\sqrt{13} \cdot \sqrt{14}} = \frac{5}{\sqrt{182}}$.</p><p>Ответ: $\frac{5}{\sqrt{182}}$.</p>"
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    "book" => Illuminate\Database\Eloquent\Collection {#1251
      #items: array:1 [
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            "field_class" => Illuminate\Database\Eloquent\Collection {#1175
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                1 => App\Models\Term {#1172
                  #connection: "mysql"
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                  #attributes: array:6 [ …6]
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            "field_publisher" => Illuminate\Database\Eloquent\Collection {#1171
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                  #attributes: array:6 [ …6]
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            "field_author" => Illuminate\Database\Eloquent\Collection {#1169
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                1 => App\Models\Term {#1170
                  #connection: "mysql"
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                  #attributes: array:12 [ …12]
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                2 => App\Models\Term {#1168
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
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                  +exists: true
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                  #escapeWhenCastingToString: false
                  #attributes: array:12 [ …12]
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                3 => App\Models\Term {#1225
                  #connection: "mysql"
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                4 => App\Models\Term {#1226
                  #connection: "mysql"
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                  #escapeWhenCastingToString: false
                  #attributes: array:12 [ …12]
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                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1228
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_book_type" => Illuminate\Database\Eloquent\Collection {#1229
              #items: array:1 [
                0 => App\Models\Term {#1230
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
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                  +preventsLazyLoading: false
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                  #attributes: array:10 [ …10]
                  #original: array:10 [ …10]
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                  #touches: []
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                  #hidden: []
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                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_country" => Illuminate\Database\Eloquent\Collection {#1231
              #items: array:1 [
                0 => App\Models\Term {#1232
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
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                  #escapeWhenCastingToString: false
                  #attributes: array:6 [ …6]
                  #original: array:6 [ …6]
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                  #attributeCastCache: []
                  #dateFormat: null
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                  #relations: []
                  #touches: []
                  +timestamps: true
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                  #hidden: []
                  #visible: []
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                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_city" => Illuminate\Database\Eloquent\Collection {#1233
              #items: array:1 [
                0 => App\Models\Term {#1234
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
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                  +preventsLazyLoading: false
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                  #escapeWhenCastingToString: false
                  #attributes: array:6 [ …6]
                  #original: array:6 [ …6]
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                  #attributeCastCache: []
                  #dateFormat: null
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                  #hidden: []
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                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_series" => Illuminate\Database\Eloquent\Collection {#1235
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_umk" => Illuminate\Database\Eloquent\Collection {#1236
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1237
              #items: array:1 [
                0 => App\Models\Term {#1238
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
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                  #escapeWhenCastingToString: false
                  #attributes: array:6 [ …6]
                  #original: array:6 [ …6]
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                  #dateFormat: null
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                  #touches: []
                  +timestamps: true
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                  #hidden: []
                  #visible: []
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                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1239
              #items: array:1 [
                0 => App\Models\Term {#1240
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
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                  #escapeWhenCastingToString: false
                  #attributes: array:10 [ …10]
                  #original: array:10 [ …10]
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                  #attributeCastCache: []
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                  #touches: []
                  +timestamps: true
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                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_publication_number" => "11"
            "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1241
              #items: array:1 [
                0 => App\Models\Term {#1242
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
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                  #escapeWhenCastingToString: false
                  #attributes: array:6 [ …6]
                  #original: array:6 [ …6]
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                  #relations: []
                  #touches: []
                  +timestamps: true
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                  #hidden: []
                  #visible: []
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                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1243
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_under_the_edition_degree" => null
            "field_cover_description" => "с ромбами"
            "field_publication_year" => "2019"
            "field_publication_year_until" => null
            "field_part" => ""
            "field_part_writing" => ""
            "field_second_foreign_language" => null
            "field_for_whom" => "Учебник для общеобразовательных организаций"
            "field_allowed" => "Допущено Министерством просвещения Российской Федерации"
            "field_reserve_field" => "Математика: алгебра и начала математического анализа, геометрия"
            "field_link_to_source" => null
            "field_tasks_count" => "1147"
            "field_priority" => "12"
            "field_default_folder" => "/geometrija_10/atanasjan-u23/"
            "field_isbn" => "978-5-09-103606-0 (2023)"
            "field_cover" => array:1 [
              0 => "/media/geometrija_10/atanasjan-u23/covers/cover1.webp?ts=1739363242"
            ]
            "field_cover_alts" => array:1 [
              0 => ""
            ]
            "field_covers" => array:1 [
              0 => array:4 [
                "path" => "/media/geometrija_10/atanasjan-u23/covers/cover1.webp?ts=1739363242"
                "alt" => ""
                "width" => "1200"
                "height" => "1661"
              ]
            ]
            "field_popular_book" => null
            "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1244
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_new_book" => Illuminate\Database\Eloquent\Collection {#1245
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_old_book" => Illuminate\Database\Eloquent\Collection {#1246
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_url" => "/10-klass/geometrija/atanasjan-uchebnik"
            "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1247
              #items: array:1 [
                0 => App\Models\Term {#1248
                  #connection: "mysql"
                  #table: "terms"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: false
                  #with: []
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                  #perPage: 15
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                  #escapeWhenCastingToString: false
                  #attributes: array:6 [ …6]
                  #original: array:6 [ …6]
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                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
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            "field_description_bottom" => null
            "breadcrumbs" => array:3 [
              "class" => 381
              "subject" => 543
              "class_subject" => 392
            ]
          ]
          #original: array:50 [
            "id" => 36
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_tree_default_status" => "tasks"
            "field_pages_status" => null
            "field_subject" => Illuminate\Database\Eloquent\Collection {#1165}
            "field_class" => Illuminate\Database\Eloquent\Collection {#1175}
            "field_publisher" => Illuminate\Database\Eloquent\Collection {#1171}
            "field_author" => Illuminate\Database\Eloquent\Collection {#1169}
            "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1228}
            "field_book_type" => Illuminate\Database\Eloquent\Collection {#1229}
            "field_country" => Illuminate\Database\Eloquent\Collection {#1231}
            "field_city" => Illuminate\Database\Eloquent\Collection {#1233}
            "field_series" => Illuminate\Database\Eloquent\Collection {#1235}
            "field_umk" => Illuminate\Database\Eloquent\Collection {#1236}
            "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1237}
            "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1239}
            "field_publication_number" => "11"
            "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1241}
            "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1243}
            "field_under_the_edition_degree" => null
            "field_cover_description" => "с ромбами"
            "field_publication_year" => "2019"
            "field_publication_year_until" => null
            "field_part" => ""
            "field_part_writing" => ""
            "field_second_foreign_language" => null
            "field_for_whom" => "Учебник для общеобразовательных организаций"
            "field_allowed" => "Допущено Министерством просвещения Российской Федерации"
            "field_reserve_field" => "Математика: алгебра и начала математического анализа, геометрия"
            "field_link_to_source" => null
            "field_tasks_count" => "1147"
            "field_priority" => "12"
            "field_default_folder" => "/geometrija_10/atanasjan-u23/"
            "field_isbn" => "978-5-09-103606-0 (2023)"
            "field_cover" => array:1 [
              0 => "/media/geometrija_10/atanasjan-u23/covers/cover1.webp?ts=1739363242"
            ]
            "field_cover_alts" => array:1 [
              0 => ""
            ]
            "field_covers" => array:1 [
              0 => array:4 [
                "path" => "/media/geometrija_10/atanasjan-u23/covers/cover1.webp?ts=1739363242"
                "alt" => ""
                "width" => "1200"
                "height" => "1661"
              ]
            ]
            "field_popular_book" => null
            "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1244}
            "field_new_book" => Illuminate\Database\Eloquent\Collection {#1245}
            "field_old_book" => Illuminate\Database\Eloquent\Collection {#1246}
            "field_url" => "/10-klass/geometrija/atanasjan-uchebnik"
            "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1247}
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "breadcrumbs" => array:3 [
              "class" => 381
              "subject" => 543
              "class_subject" => 392
            ]
          ]
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            0 => "*"
          ]
        }
      ]
      #escapeWhenCastingToString: false
    }
    "page" => Illuminate\Database\Eloquent\Collection {#1256
      #items: array:1 [
        0 => App\Models\BookPage {#1255
          #connection: "mysql"
          #table: "book_pages"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: true
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:21 [
            "id" => 933961
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_page_start" => "179"
            "field_url" => "/10-klass/geometrija/atanasjan-uchebnik/page-179"
            "field_display_title" => "179"
            "field_folder" => "1"
            "field_image_name" => "179"
            "field_branch_parent" => Illuminate\Database\Eloquent\Collection {#1257
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_weight" => "0"
            "field_book_parent" => Illuminate\Database\Eloquent\Collection {#1258
              #items: array:1 [
                0 => App\Models\Book {#1176}
              ]
              #escapeWhenCastingToString: false
            }
            "field_metatags_title" => null
            "field_metatags_description" => null
            "field_h1" => null
            "field_description_top" => null
            "field_description_bottom" => null
            "edition_groups" => Illuminate\Database\Eloquent\Collection {#1259
              #items: []
              #escapeWhenCastingToString: false
            }
            "content" => Illuminate\Database\Eloquent\Collection {#1269
              #items: array:1 [
                0 => App\Models\Element {#1268
                  #connection: "mysql"
                  #table: "elements"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:6 [ …6]
                  #original: array:6 [ …6]
                  #changes: []
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                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "next" => array:2 [
              "refs" => "933962"
              "type" => "book_page"
            ]
            "previous" => array:2 [
              "refs" => "933960"
              "type" => "book_page"
            ]
            "tasks" => Illuminate\Database\Eloquent\Collection {#1481
              #items: array:11 [
                0 => App\Models\Task {#1499
                  #connection: "mysql"
                  #table: "tasks"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:24 [ …24]
                  #original: array:24 [ …24]
                  #changes: []
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                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
                1 => App\Models\Task {#1506
                  #connection: "mysql"
                  #table: "tasks"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:24 [ …24]
                  #original: array:24 [ …24]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
                2 => App\Models\Task {#1509
                  #connection: "mysql"
                  #table: "tasks"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:24 [ …24]
                  #original: array:24 [ …24]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
                3 => App\Models\Task {#1533
                  #connection: "mysql"
                  #table: "tasks"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:24 [ …24]
                  #original: array:24 [ …24]
                  #changes: []
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                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
                4 => App\Models\Task {#1536
                  #connection: "mysql"
                  #table: "tasks"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:24 [ …24]
                  #original: array:24 [ …24]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
                5 => App\Models\Task {#1535
                  #connection: "mysql"
                  #table: "tasks"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:24 [ …24]
                  #original: array:24 [ …24]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
                6 => App\Models\Task {#1537
                  #connection: "mysql"
                  #table: "tasks"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:24 [ …24]
                  #original: array:24 [ …24]
                  #changes: []
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                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
                  #observables: []
                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
                7 => App\Models\Task {#1557
                  #connection: "mysql"
                  #table: "tasks"
                  #primaryKey: "id"
                  #keyType: "int"
                  +incrementing: true
                  #with: []
                  #withCount: []
                  +preventsLazyLoading: false
                  #perPage: 15
                  +exists: true
                  +wasRecentlyCreated: false
                  #escapeWhenCastingToString: false
                  #attributes: array:24 [ …24]
                  #original: array:24 [ …24]
                  #changes: []
                  #casts: []
                  #classCastCache: []
                  #attributeCastCache: []
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№709 (с. 179)
Условие. №709 (с. 179)
скриншот условия
Геометрия, 10-11 класс Учебник, авторы: Атанасян Левон Сергеевич, Бутузов Валентин Фёдорович, Кадомцев Сергей Борисович, Позняк Эдуард Генрихович, Киселёва Людмила Сергеевна, издательство Просвещение, Москва, 2019, коричневого цвета, страница 179, номер 709, Условие

709. В прямоугольном параллелепипеде ABCDA₁B₁C₁D₁ AB = 1, ВС = 2, ВВ₁ = 3. Вычислите косинус угла между прямыми: а) АС и D₁B; б) AB₁ и ВС₁; в) A₁D и АС₁.

Решение 2. №709 (с. 179)
Геометрия, 10-11 класс Учебник, авторы: Атанасян Левон Сергеевич, Бутузов Валентин Фёдорович, Кадомцев Сергей Борисович, Позняк Эдуард Генрихович, Киселёва Людмила Сергеевна, издательство Просвещение, Москва, 2019, коричневого цвета, страница 179, номер 709, Решение 2
Геометрия, 10-11 класс Учебник, авторы: Атанасян Левон Сергеевич, Бутузов Валентин Фёдорович, Кадомцев Сергей Борисович, Позняк Эдуард Генрихович, Киселёва Людмила Сергеевна, издательство Просвещение, Москва, 2019, коричневого цвета, страница 179, номер 709, Решение 2 (продолжение 2)
Решение 3. №709 (с. 179)
Геометрия, 10-11 класс Учебник, авторы: Атанасян Левон Сергеевич, Бутузов Валентин Фёдорович, Кадомцев Сергей Борисович, Позняк Эдуард Генрихович, Киселёва Людмила Сергеевна, издательство Просвещение, Москва, 2019, коричневого цвета, страница 179, номер 709, Решение 3
Геометрия, 10-11 класс Учебник, авторы: Атанасян Левон Сергеевич, Бутузов Валентин Фёдорович, Кадомцев Сергей Борисович, Позняк Эдуард Генрихович, Киселёва Людмила Сергеевна, издательство Просвещение, Москва, 2019, коричневого цвета, страница 179, номер 709, Решение 3 (продолжение 2)
Решение 4. №709 (с. 179)
Геометрия, 10-11 класс Учебник, авторы: Атанасян Левон Сергеевич, Бутузов Валентин Фёдорович, Кадомцев Сергей Борисович, Позняк Эдуард Генрихович, Киселёва Людмила Сергеевна, издательство Просвещение, Москва, 2019, коричневого цвета, страница 179, номер 709, Решение 4
Решение 5. №709 (с. 179)
Решение 6. №709 (с. 179)

Для решения задачи воспользуемся координатным методом. Введем прямоугольную систему координат с началом в точке $A(0, 0, 0)$. Направим ось $Ox$ вдоль ребра $AB$, ось $Oy$ вдоль ребра $AD$ и ось $Oz$ вдоль ребра $AA_1$.

В этой системе координат, с учетом длин ребер $AB=1$, $BC=AD=2$ и $BB_1=AA_1=3$, вершины параллелепипеда будут иметь следующие координаты:

  • $A(0, 0, 0)$
  • $B(1, 0, 0)$
  • $C(1, 2, 0)$
  • $D(0, 2, 0)$
  • $A_1(0, 0, 3)$
  • $B_1(1, 0, 3)$
  • $C_1(1, 2, 3)$
  • $D_1(0, 2, 3)$

Косинус угла $\alpha$ между двумя прямыми, заданными направляющими векторами $\vec{a}$ и $\vec{b}$, вычисляется по формуле скалярного произведения векторов:

$cos(\alpha) = \frac{|\vec{a} \cdot \vec{b}|}{|\vec{a}| \cdot |\vec{b}|}$

а) AC и D?B

Найдем координаты направляющих векторов для прямых $AC$ и $D_1B$.

Вектор $\vec{AC}$ имеет координаты: $\vec{AC} = \{C_x - A_x; C_y - A_y; C_z - A_z\} = \{1-0; 2-0; 0-0\} = \{1; 2; 0\}$.

Вектор $\vec{D_1B}$ имеет координаты: $\vec{D_1B} = \{B_x - D_{1x}; B_y - D_{1y}; B_z - D_{1z}\} = \{1-0; 0-2; 0-3\} = \{1; -2; -3\}$.

Вычислим скалярное произведение векторов:

$\vec{AC} \cdot \vec{D_1B} = 1 \cdot 1 + 2 \cdot (-2) + 0 \cdot (-3) = 1 - 4 + 0 = -3$.

Найдем длины (модули) векторов:

$|\vec{AC}| = \sqrt{1^2 + 2^2 + 0^2} = \sqrt{1 + 4 + 0} = \sqrt{5}$.

$|\vec{D_1B}| = \sqrt{1^2 + (-2)^2 + (-3)^2} = \sqrt{1 + 4 + 9} = \sqrt{14}$.

Теперь вычислим косинус угла $\alpha$ между прямыми:

$cos(\alpha) = \frac{|\vec{AC} \cdot \vec{D_1B}|}{|\vec{AC}| \cdot |\vec{D_1B}|} = \frac{|-3|}{\sqrt{5} \cdot \sqrt{14}} = \frac{3}{\sqrt{70}}$.

Ответ: $\frac{3}{\sqrt{70}}$.

б) AB? и BC?

Найдем координаты направляющих векторов для прямых $AB_1$ и $BC_1$.

Вектор $\vec{AB_1}$: $\vec{AB_1} = \{B_{1x} - A_x; B_{1y} - A_y; B_{1z} - A_z\} = \{1-0; 0-0; 3-0\} = \{1; 0; 3\}$.

Вектор $\vec{BC_1}$: $\vec{BC_1} = \{C_{1x} - B_x; C_{1y} - B_y; C_{1z} - B_z\} = \{1-1; 2-0; 3-0\} = \{0; 2; 3\}$.

Вычислим скалярное произведение векторов:

$\vec{AB_1} \cdot \vec{BC_1} = 1 \cdot 0 + 0 \cdot 2 + 3 \cdot 3 = 0 + 0 + 9 = 9$.

Найдем длины векторов:

$|\vec{AB_1}| = \sqrt{1^2 + 0^2 + 3^2} = \sqrt{1 + 9} = \sqrt{10}$.

$|\vec{BC_1}| = \sqrt{0^2 + 2^2 + 3^2} = \sqrt{4 + 9} = \sqrt{13}$.

Вычислим косинус угла $\beta$ между прямыми:

$cos(\beta) = \frac{|\vec{AB_1} \cdot \vec{BC_1}|}{|\vec{AB_1}| \cdot |\vec{BC_1}|} = \frac{|9|}{\sqrt{10} \cdot \sqrt{13}} = \frac{9}{\sqrt{130}}$.

Ответ: $\frac{9}{\sqrt{130}}$.

в) A?D и AC?

Найдем координаты направляющих векторов для прямых $A_1D$ и $AC_1$.

Вектор $\vec{A_1D}$: $\vec{A_1D} = \{D_x - A_{1x}; D_y - A_{1y}; D_z - A_{1z}\} = \{0-0; 2-0; 0-3\} = \{0; 2; -3\}$.

Вектор $\vec{AC_1}$: $\vec{AC_1} = \{C_{1x} - A_x; C_{1y} - A_y; C_{1z} - A_z\} = \{1-0; 2-0; 3-0\} = \{1; 2; 3\}$.

Вычислим скалярное произведение векторов:

$\vec{A_1D} \cdot \vec{AC_1} = 0 \cdot 1 + 2 \cdot 2 + (-3) \cdot 3 = 0 + 4 - 9 = -5$.

Найдем длины векторов:

$|\vec{A_1D}| = \sqrt{0^2 + 2^2 + (-3)^2} = \sqrt{4 + 9} = \sqrt{13}$.

$|\vec{AC_1}| = \sqrt{1^2 + 2^2 + 3^2} = \sqrt{1 + 4 + 9} = \sqrt{14}$.

Вычислим косинус угла $\gamma$ между прямыми:

$cos(\gamma) = \frac{|\vec{A_1D} \cdot \vec{AC_1}|}{|\vec{A_1D}| \cdot |\vec{AC_1}|} = \frac{|-5|}{\sqrt{13} \cdot \sqrt{14}} = \frac{5}{\sqrt{182}}$.

Ответ: $\frac{5}{\sqrt{182}}$.

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