Номер 608, страница 143 - гдз по геометрии 9 класс учебник Мерзляк, Полонский

Геометрия, 9 класс Учебник, авторы: Мерзляк Аркадий Григорьевич, Полонский Виталий Борисович, Якир Михаил Семёнович, издательство Просвещение, Москва, 2019, оранжевого цвета

Авторы: Мерзляк А. Г., Полонский В. Б., Якир М. С.

Тип: Учебник

Издательство: Просвещение, Вентана-граф

Год издания: 2019 - 2026

Цвет обложки: оранжевый, зелёный

ISBN: 978-5-09-104934-3

Допущено Министерством просвещения Российской Федерации

Глава 4. Векторы. Параграф 16. Скалярное произведение векторов. Упражнения - номер 608, страница 143.

App\Models\Task {#1030 // resources/views/models/task/default.blade.php
  #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 [
    "id" => 657366
    "created_at" => "2026-04-10 13:58:26"
    "updated_at" => null
    "field_page_start" => "143"
    "field_page_end" => null
    "field_url" => "/9-klass/geometrija/merzlyak-uchebnik/608"
    "field_display_title" => "608"
    "field_outside_task" => null
    "field_task_type" => Illuminate\Database\Eloquent\Collection {#1037
      #items: array:1 [
        0 => App\Models\Term {#1036
          #connection: "mysql"
          #table: "terms"
          #primaryKey: "id"
          #keyType: "int"
          +incrementing: false
          #with: []
          #withCount: []
          +preventsLazyLoading: false
          #perPage: 15
          +exists: true
          +wasRecentlyCreated: false
          #escapeWhenCastingToString: false
          #attributes: array:6 [
            "id" => 26
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "name" => "номер"
            "field_cases" => array:6 [
              "field_accusative_case" => "номер"
              "field_creative_case" => "номером"
              "field_dative_case" => "номеру"
              "field_genitive_case" => "номера"
              "field_nominative_case" => "номер"
              "field_prepositional_case" => "номере"
            ]
            "field_short_name" => ""
          ]
          #original: array:6 [
            "id" => 26
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "name" => "номер"
            "field_cases" => array:6 [
              "field_accusative_case" => "номер"
              "field_creative_case" => "номером"
              "field_dative_case" => "номеру"
              "field_genitive_case" => "номера"
              "field_nominative_case" => "номер"
              "field_prepositional_case" => "номере"
            ]
            "field_short_name" => ""
          ]
          #changes: []
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          #attributeCastCache: []
          #dateFormat: null
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          #dispatchesEvents: []
          #observables: []
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          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
      ]
      #escapeWhenCastingToString: false
    }
    "field_metatags_title" => null
    "field_metatags_description" => null
    "field_h1" => null
    "field_description_top" => null
    "field_description_bottom" => null
    "field_match" => null
    "breadcrumbs" => []
    "edition_groups" => Illuminate\Database\Eloquent\Collection {#1035
      #items: []
      #escapeWhenCastingToString: false
    }
    "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1078
      #items: array:1 [
        0 => App\Models\Branch {#1034
          #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" => 656546
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Векторы"
            "field_branch_order" => "4"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1039
              #items: array:1 [
                0 => App\Models\Term {#1038
                  #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: []
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                  #attributeCastCache: []
                  #dateFormat: null
                  #appends: []
                  #dispatchesEvents: []
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                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "102"
            "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
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            "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 {#1040
              #items: array:1 [
                0 => App\Models\Book {#1041
                  #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: []
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                  #dateFormat: null
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                  +timestamps: true
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                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1075
              #items: []
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 656546
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Векторы"
            "field_branch_order" => "4"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1039}
            "field_page_start" => "102"
            "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 {#1040}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1075}
          ]
          #changes: []
          #casts: []
          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
          #appends: []
          #dispatchesEvents: []
          #observables: []
          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
      ]
      #escapeWhenCastingToString: false
    }
    "parent_branches" => Illuminate\Database\Eloquent\Collection {#1233
      #items: array:3 [
        0 => App\Models\Branch {#1243
          #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" => 656546
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Векторы"
            "field_branch_order" => "4"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1247
              #items: array:1 [
                0 => App\Models\Term {#1244
                  #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" => "102"
            "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 {#1282
              #items: array:1 [
                0 => App\Models\Book {#1246
                  #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 [
                    "id" => 905
                    "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 {#1248
                      #items: array:1 [
                        0 => App\Models\Term {#1245
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:10 [ …10]
                          #original: array:10 [ …10]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
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                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_class" => Illuminate\Database\Eloquent\Collection {#1249
                      #items: array:1 [
                        0 => App\Models\Term {#1250
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:6 [ …6]
                          #original: array:6 [ …6]
                          #changes: []
                          #casts: []
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                          #attributeCastCache: []
                          #dateFormat: null
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                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_publisher" => Illuminate\Database\Eloquent\Collection {#1251
                      #items: array:2 [
                        0 => App\Models\Term {#1252
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:6 [ …6]
                          #original: array:6 [ …6]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
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                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                        1 => App\Models\Term {#1253
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:6 [ …6]
                          #original: array:6 [ …6]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
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                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_author" => Illuminate\Database\Eloquent\Collection {#1254
                      #items: array:3 [
                        0 => App\Models\Term {#1255
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:12 [ …12]
                          #original: array:12 [ …12]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
                          #dateFormat: null
                          #appends: []
                          #dispatchesEvents: []
                          #observables: []
                          #relations: []
                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                        1 => App\Models\Term {#1256
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:12 [ …12]
                          #original: array:12 [ …12]
                          #changes: []
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                          #attributeCastCache: []
                          #dateFormat: null
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                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                        2 => App\Models\Term {#1257
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:12 [ …12]
                          #original: array:12 [ …12]
                          #changes: []
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                          #attributeCastCache: []
                          #dateFormat: null
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                          #touches: []
                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1258
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_book_type" => Illuminate\Database\Eloquent\Collection {#1259
                      #items: array:1 [
                        0 => App\Models\Term {#1260
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
                          #escapeWhenCastingToString: false
                          #attributes: array:10 [ …10]
                          #original: array:10 [ …10]
                          #changes: []
                          #casts: []
                          #classCastCache: []
                          #attributeCastCache: []
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                          #appends: []
                          #dispatchesEvents: []
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                          #touches: []
                          +timestamps: true
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                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_country" => Illuminate\Database\Eloquent\Collection {#1261
                      #items: array:1 [
                        0 => App\Models\Term {#1262
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
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                          #with: []
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                          +timestamps: true
                          +usesUniqueIds: false
                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_city" => Illuminate\Database\Eloquent\Collection {#1263
                      #items: array:1 [
                        0 => App\Models\Term {#1264
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
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                          #escapeWhenCastingToString: false
                          #attributes: array:6 [ …6]
                          #original: array:6 [ …6]
                          #changes: []
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                          +timestamps: true
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                          #hidden: []
                          #visible: []
                          #fillable: []
                          #guarded: array:1 [ …1]
                        }
                      ]
                      #escapeWhenCastingToString: false
                    }
                    "field_series" => Illuminate\Database\Eloquent\Collection {#1265
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_umk" => Illuminate\Database\Eloquent\Collection {#1266
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1267
                      #items: []
                      #escapeWhenCastingToString: false
                    }
                    "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1268
                      #items: array:1 [
                        0 => App\Models\Term {#1269
                          #connection: "mysql"
                          #table: "terms"
                          #primaryKey: "id"
                          #keyType: "int"
                          +incrementing: false
                          #with: []
                          #withCount: []
                          +preventsLazyLoading: false
                          #perPage: 15
                          +exists: true
                          +wasRecentlyCreated: false
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            0 => "*"
          ]
        }
        1 => App\Models\Branch {#1281
          #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" => 656559
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Скалярное произведение векторов"
            "field_branch_order" => "16"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1286
              #items: array:1 [
                0 => App\Models\Term {#1283
                  #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" => "136"
            "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 {#1285
              #items: array:1 [
                0 => App\Models\Book {#1246}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1284
              #items: array:1 [
                0 => App\Models\Branch {#1034}
              ]
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 656559
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Скалярное произведение векторов"
            "field_branch_order" => "16"
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1286}
            "field_page_start" => "136"
            "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 {#1285}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1284}
          ]
          #changes: []
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          #attributeCastCache: []
          #dateFormat: null
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          #touches: []
          +timestamps: true
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          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        2 => App\Models\Branch {#1287
          #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" => 656561
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Упражнения"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1288
              #items: []
              #escapeWhenCastingToString: false
            }
            "field_page_start" => "140"
            "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 {#1289
              #items: array:1 [
                0 => App\Models\Book {#1246}
              ]
              #escapeWhenCastingToString: false
            }
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1298
              #items: array:1 [
                0 => App\Models\Branch {#1297
                  #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: []
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                  #classCastCache: []
                  #attributeCastCache: []
                  #dateFormat: null
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                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
          ]
          #original: array:24 [
            "id" => 656561
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "field_display_title" => "Упражнения"
            "field_branch_order" => null
            "field_url" => null
            "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1288}
            "field_page_start" => "140"
            "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 {#1289}
            "branch_parent" => Illuminate\Database\Eloquent\Collection {#1298}
          ]
          #changes: []
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          #attributeCastCache: []
          #dateFormat: null
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          #touches: []
          +timestamps: true
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          #hidden: []
          #visible: []
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          #guarded: array:1 [
            0 => "*"
          ]
        }
      ]
      #escapeWhenCastingToString: false
    }
    "content" => Illuminate\Database\Eloquent\Collection {#1190
      #items: array:6 [
        0 => App\Models\Element {#1240
          #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" => 813254
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1153
              #items: array:1 [
                0 => App\Models\Edition {#1116
                  #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: []
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                  #attributeCastCache: []
                  #dateFormat: null
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                  #touches: []
                  +timestamps: true
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                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "task" => array:2 [
              "refs" => "657366"
              "type" => "task"
            ]
            "text" => "<p><strong>608.</strong> Найдите косинусы углов треугольника с вершинами $A (1; 6)$, $B (-2; 3)$, $C (2; -1)$.</p>"
            "img" => array:1 [
              0 => array:5 [
                "name" => "608-1.png"
                "alt" => null
                "width" => "603"
                "height" => 85
                "path" => "/media/geometrija_09/merzlyak/0-00/608-1.webp?ts=1738828561"
              ]
            ]
          ]
          #original: array:7 [
            "id" => 813254
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1153}
            "task" => array:2 [
              "refs" => "657366"
              "type" => "task"
            ]
            "text" => "<p><strong>608.</strong> Найдите косинусы углов треугольника с вершинами $A (1; 6)$, $B (-2; 3)$, $C (2; -1)$.</p>"
            "img" => array:1 [
              0 => array:5 [
                "name" => "608-1.png"
                "alt" => null
                "width" => "603"
                "height" => 85
                "path" => "/media/geometrija_09/merzlyak/0-00/608-1.webp?ts=1738828561"
              ]
            ]
          ]
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          #hidden: []
          #visible: []
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          #guarded: array:1 [
            0 => "*"
          ]
        }
        1 => App\Models\Element {#1197
          #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" => 814445
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1228
              #items: array:1 [
                0 => App\Models\Edition {#1230
                  #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: []
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                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "task" => array:2 [
              "refs" => "657366"
              "type" => "task"
            ]
            "img" => array:1 [
              0 => array:5 [
                "name" => "608-1.png"
                "alt" => null
                "width" => "694"
                "height" => 1622
                "path" => "/media/geometrija_09/merzlyak/1-00/608-1.webp?ts=1738828969"
              ]
            ]
          ]
          #original: array:6 [
            "id" => 814445
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1228}
            "task" => array:2 [
              "refs" => "657366"
              "type" => "task"
            ]
            "img" => array:1 [
              0 => array:5 [
                "name" => "608-1.png"
                "alt" => null
                "width" => "694"
                "height" => 1622
                "path" => "/media/geometrija_09/merzlyak/1-00/608-1.webp?ts=1738828969"
              ]
            ]
          ]
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          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        2 => App\Models\Element {#1224
          #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" => 812972
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1221
              #items: array:1 [
                0 => App\Models\Edition {#1222
                  #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: []
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                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "task" => array:2 [
              "refs" => "657366"
              "type" => "task"
            ]
            "img" => array:1 [
              0 => array:5 [
                "name" => "608-1.jpg"
                "alt" => null
                "width" => "600"
                "height" => 843
                "path" => "/media/geometrija_09/merzlyak/2-00/608-1.webp?ts=1738828225"
              ]
            ]
          ]
          #original: array:6 [
            "id" => 812972
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1221}
            "task" => array:2 [
              "refs" => "657366"
              "type" => "task"
            ]
            "img" => array:1 [
              0 => array:5 [
                "name" => "608-1.jpg"
                "alt" => null
                "width" => "600"
                "height" => 843
                "path" => "/media/geometrija_09/merzlyak/2-00/608-1.webp?ts=1738828225"
              ]
            ]
          ]
          #changes: []
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          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
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          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        3 => App\Models\Element {#1214
          #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" => 819789
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1215
              #items: array:1 [
                0 => App\Models\Edition {#1212
                  #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: []
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                  #relations: []
                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "task" => array:2 [
              "refs" => "657366"
              "type" => "task"
            ]
            "img" => array:1 [
              0 => array:5 [
                "name" => "608-1.png"
                "alt" => null
                "width" => "429"
                "height" => 1556
                "path" => "/media/geometrija_09/merzlyak/3-00/608-1.webp?ts=1738827731"
              ]
            ]
          ]
          #original: array:6 [
            "id" => 819789
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1215}
            "task" => array:2 [
              "refs" => "657366"
              "type" => "task"
            ]
            "img" => array:1 [
              0 => array:5 [
                "name" => "608-1.png"
                "alt" => null
                "width" => "429"
                "height" => 1556
                "path" => "/media/geometrija_09/merzlyak/3-00/608-1.webp?ts=1738827731"
              ]
            ]
          ]
          #changes: []
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          #classCastCache: []
          #attributeCastCache: []
          #dateFormat: null
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          #relations: []
          #touches: []
          +timestamps: true
          +usesUniqueIds: false
          #hidden: []
          #visible: []
          #fillable: []
          #guarded: array:1 [
            0 => "*"
          ]
        }
        4 => App\Models\Element {#1208
          #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" => 814073
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1207
              #items: array:1 [
                0 => App\Models\Edition {#1206
                  #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: []
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                  #touches: []
                  +timestamps: true
                  +usesUniqueIds: false
                  #hidden: []
                  #visible: []
                  #fillable: []
                  #guarded: array:1 [ …1]
                }
              ]
              #escapeWhenCastingToString: false
            }
            "task" => array:2 [
              "refs" => "657366"
              "type" => "task"
            ]
            "img" => array:1 [
              0 => array:5 [
                "name" => "608-1.png"
                "alt" => null
                "width" => "1400"
                "height" => 1624
                "path" => "/media/geometrija_09/merzlyak/4-00/608-1.webp?ts=1738828870"
              ]
            ]
          ]
          #original: array:6 [
            "id" => 814073
            "created_at" => "2026-04-10 13:58:26"
            "updated_at" => null
            "edition" => Illuminate\Database\Eloquent\Collection {#1207}
            "task" => array:2 [
              "refs" => "657366"
              "type" => "task"
            ]
            "img" => array:1 [
              0 => array:5 [
                "name" => "608-1.png"
                "alt" => null
                "width" => "1400"
                "height" => 1624
                "path" => "/media/geometrija_09/merzlyak/4-00/608-1.webp?ts=1738828870"
              ]
            ]
          ]
          #changes: []
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          #classCastCache: []
          #attributeCastCache: []
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            "text" => "<p>Для нахождения косинусов углов треугольника с заданными вершинами, мы можем использовать векторы и их скалярное произведение. Косинус угла $\theta$ между двумя векторами $\vec{a}$ и $\vec{b}$ находится по формуле:</p><p>$\cos(\theta) = \frac{\vec{a} \cdot \vec{b}}{|\vec{a}| \cdot |\vec{b}|}$</p><p>где $\vec{a} \cdot \vec{b}$ - скалярное произведение векторов, а $|\vec{a}|$ и $|\vec{b}|$ - их длины (модули).</p><p>Даны вершины треугольника: $A(1; 6)$, $B(-2; 3)$, $C(2; -1)$.</p><p><strong>Косинус угла A</strong></p><p>Угол A образован векторами $\vec{AB}$ и $\vec{AC}$.</p><p>1. Найдем координаты этих векторов:</p><p>$\vec{AB} = (x_B - x_A; y_B - y_A) = (-2 - 1; 3 - 6) = (-3; -3)$</p><p>$\vec{AC} = (x_C - x_A; y_C - y_A) = (2 - 1; -1 - 6) = (1; -7)$</p><p>2. Найдем длины (модули) векторов:</p><p>$|\vec{AB}| = \sqrt{(-3)^2 + (-3)^2} = \sqrt{9 + 9} = \sqrt{18} = 3\sqrt{2}$</p><p>$|\vec{AC}| = \sqrt{1^2 + (-7)^2} = \sqrt{1 + 49} = \sqrt{50} = 5\sqrt{2}$</p><p>3. Найдем скалярное произведение векторов:</p><p>$\vec{AB} \cdot \vec{AC} = (-3) \cdot 1 + (-3) \cdot (-7) = -3 + 21 = 18$</p><p>4. Вычислим косинус угла A:</p><p>$\cos(A) = \frac{\vec{AB} \cdot \vec{AC}}{|\vec{AB}| \cdot |\vec{AC}|} = \frac{18}{3\sqrt{2} \cdot 5\sqrt{2}} = \frac{18}{15 \cdot 2} = \frac{18}{30} = \frac{3}{5}$</p><p>Ответ: $\cos(A) = \frac{3}{5}$</p><p><strong>Косинус угла B</strong></p><p>Угол B образован векторами $\vec{BA}$ и $\vec{BC}$.</p><p>1. Найдем координаты этих векторов:</p><p>$\vec{BA} = (x_A - x_B; y_A - y_B) = (1 - (-2); 6 - 3) = (3; 3)$</p><p>$\vec{BC} = (x_C - x_B; y_C - y_B) = (2 - (-2); -1 - 3) = (4; -4)$</p><p>2. Найдем длины векторов:</p><p>$|\vec{BA}| = \sqrt{3^2 + 3^2} = \sqrt{9 + 9} = \sqrt{18} = 3\sqrt{2}$</p><p>$|\vec{BC}| = \sqrt{4^2 + (-4)^2} = \sqrt{16 + 16} = \sqrt{32} = 4\sqrt{2}$</p><p>3. Найдем скалярное произведение векторов:</p><p>$\vec{BA} \cdot \vec{BC} = 3 \cdot 4 + 3 \cdot (-4) = 12 - 12 = 0$</p><p>4. Вычислим косинус угла B:</p><p>$\cos(B) = \frac{\vec{BA} \cdot \vec{BC}}{|\vec{BA}| \cdot |\vec{BC}|} = \frac{0}{3\sqrt{2} \cdot 4\sqrt{2}} = 0$</p><p>Ответ: $\cos(B) = 0$</p><p><strong>Косинус угла C</strong></p><p>Угол C образован векторами $\vec{CA}$ и $\vec{CB}$.</p><p>1. Найдем координаты этих векторов:</p><p>$\vec{CA} = (x_A - x_C; y_A - y_C) = (1 - 2; 6 - (-1)) = (-1; 7)$</p><p>$\vec{CB} = (x_B - x_C; y_B - y_C) = (-2 - 2; 3 - (-1)) = (-4; 4)$</p><p>2. Найдем длины векторов:</p><p>$|\vec{CA}| = \sqrt{(-1)^2 + 7^2} = \sqrt{1 + 49} = \sqrt{50} = 5\sqrt{2}$</p><p>$|\vec{CB}| = \sqrt{(-4)^2 + 4^2} = \sqrt{16 + 16} = \sqrt{32} = 4\sqrt{2}$</p><p>3. Найдем скалярное произведение векторов:</p><p>$\vec{CA} \cdot \vec{CB} = (-1) \cdot (-4) + 7 \cdot 4 = 4 + 28 = 32$</p><p>4. Вычислим косинус угла C:</p><p>$\cos(C) = \frac{\vec{CA} \cdot \vec{CB}}{|\vec{CA}| \cdot |\vec{CB}|} = \frac{32}{5\sqrt{2} \cdot 4\sqrt{2}} = \frac{32}{20 \cdot 2} = \frac{32}{40} = \frac{4}{5}$</p><p>Ответ: $\cos(C) = \frac{4}{5}$</p>"
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            "text" => "<p>Для нахождения косинусов углов треугольника с заданными вершинами, мы можем использовать векторы и их скалярное произведение. Косинус угла $\theta$ между двумя векторами $\vec{a}$ и $\vec{b}$ находится по формуле:</p><p>$\cos(\theta) = \frac{\vec{a} \cdot \vec{b}}{|\vec{a}| \cdot |\vec{b}|}$</p><p>где $\vec{a} \cdot \vec{b}$ - скалярное произведение векторов, а $|\vec{a}|$ и $|\vec{b}|$ - их длины (модули).</p><p>Даны вершины треугольника: $A(1; 6)$, $B(-2; 3)$, $C(2; -1)$.</p><p><strong>Косинус угла A</strong></p><p>Угол A образован векторами $\vec{AB}$ и $\vec{AC}$.</p><p>1. Найдем координаты этих векторов:</p><p>$\vec{AB} = (x_B - x_A; y_B - y_A) = (-2 - 1; 3 - 6) = (-3; -3)$</p><p>$\vec{AC} = (x_C - x_A; y_C - y_A) = (2 - 1; -1 - 6) = (1; -7)$</p><p>2. Найдем длины (модули) векторов:</p><p>$|\vec{AB}| = \sqrt{(-3)^2 + (-3)^2} = \sqrt{9 + 9} = \sqrt{18} = 3\sqrt{2}$</p><p>$|\vec{AC}| = \sqrt{1^2 + (-7)^2} = \sqrt{1 + 49} = \sqrt{50} = 5\sqrt{2}$</p><p>3. Найдем скалярное произведение векторов:</p><p>$\vec{AB} \cdot \vec{AC} = (-3) \cdot 1 + (-3) \cdot (-7) = -3 + 21 = 18$</p><p>4. Вычислим косинус угла A:</p><p>$\cos(A) = \frac{\vec{AB} \cdot \vec{AC}}{|\vec{AB}| \cdot |\vec{AC}|} = \frac{18}{3\sqrt{2} \cdot 5\sqrt{2}} = \frac{18}{15 \cdot 2} = \frac{18}{30} = \frac{3}{5}$</p><p>Ответ: $\cos(A) = \frac{3}{5}$</p><p><strong>Косинус угла B</strong></p><p>Угол B образован векторами $\vec{BA}$ и $\vec{BC}$.</p><p>1. Найдем координаты этих векторов:</p><p>$\vec{BA} = (x_A - x_B; y_A - y_B) = (1 - (-2); 6 - 3) = (3; 3)$</p><p>$\vec{BC} = (x_C - x_B; y_C - y_B) = (2 - (-2); -1 - 3) = (4; -4)$</p><p>2. Найдем длины векторов:</p><p>$|\vec{BA}| = \sqrt{3^2 + 3^2} = \sqrt{9 + 9} = \sqrt{18} = 3\sqrt{2}$</p><p>$|\vec{BC}| = \sqrt{4^2 + (-4)^2} = \sqrt{16 + 16} = \sqrt{32} = 4\sqrt{2}$</p><p>3. Найдем скалярное произведение векторов:</p><p>$\vec{BA} \cdot \vec{BC} = 3 \cdot 4 + 3 \cdot (-4) = 12 - 12 = 0$</p><p>4. Вычислим косинус угла B:</p><p>$\cos(B) = \frac{\vec{BA} \cdot \vec{BC}}{|\vec{BA}| \cdot |\vec{BC}|} = \frac{0}{3\sqrt{2} \cdot 4\sqrt{2}} = 0$</p><p>Ответ: $\cos(B) = 0$</p><p><strong>Косинус угла C</strong></p><p>Угол C образован векторами $\vec{CA}$ и $\vec{CB}$.</p><p>1. Найдем координаты этих векторов:</p><p>$\vec{CA} = (x_A - x_C; y_A - y_C) = (1 - 2; 6 - (-1)) = (-1; 7)$</p><p>$\vec{CB} = (x_B - x_C; y_B - y_C) = (-2 - 2; 3 - (-1)) = (-4; 4)$</p><p>2. Найдем длины векторов:</p><p>$|\vec{CA}| = \sqrt{(-1)^2 + 7^2} = \sqrt{1 + 49} = \sqrt{50} = 5\sqrt{2}$</p><p>$|\vec{CB}| = \sqrt{(-4)^2 + 4^2} = \sqrt{16 + 16} = \sqrt{32} = 4\sqrt{2}$</p><p>3. Найдем скалярное произведение векторов:</p><p>$\vec{CA} \cdot \vec{CB} = (-1) \cdot (-4) + 7 \cdot 4 = 4 + 28 = 32$</p><p>4. Вычислим косинус угла C:</p><p>$\cos(C) = \frac{\vec{CA} \cdot \vec{CB}}{|\vec{CA}| \cdot |\vec{CB}|} = \frac{32}{5\sqrt{2} \cdot 4\sqrt{2}} = \frac{32}{20 \cdot 2} = \frac{32}{40} = \frac{4}{5}$</p><p>Ответ: $\cos(C) = \frac{4}{5}$</p>"
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№608 (с. 143)
Условие. №608 (с. 143)
скриншот условия
Геометрия, 9 класс Учебник, авторы: Мерзляк Аркадий Григорьевич, Полонский Виталий Борисович, Якир Михаил Семёнович, издательство Просвещение, Москва, 2019, оранжевого цвета, страница 143, номер 608, Условие

608. Найдите косинусы углов треугольника с вершинами $A (1; 6)$, $B (-2; 3)$, $C (2; -1)$.

Решение 1. №608 (с. 143)
Геометрия, 9 класс Учебник, авторы: Мерзляк Аркадий Григорьевич, Полонский Виталий Борисович, Якир Михаил Семёнович, издательство Просвещение, Москва, 2019, оранжевого цвета, страница 143, номер 608, Решение 1
Решение 2. №608 (с. 143)
Геометрия, 9 класс Учебник, авторы: Мерзляк Аркадий Григорьевич, Полонский Виталий Борисович, Якир Михаил Семёнович, издательство Просвещение, Москва, 2019, оранжевого цвета, страница 143, номер 608, Решение 2
Решение 3. №608 (с. 143)
Геометрия, 9 класс Учебник, авторы: Мерзляк Аркадий Григорьевич, Полонский Виталий Борисович, Якир Михаил Семёнович, издательство Просвещение, Москва, 2019, оранжевого цвета, страница 143, номер 608, Решение 3
Решение 4. №608 (с. 143)
Решение 6. №608 (с. 143)

Для нахождения косинусов углов треугольника с заданными вершинами, мы можем использовать векторы и их скалярное произведение. Косинус угла $\theta$ между двумя векторами $\vec{a}$ и $\vec{b}$ находится по формуле:

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

где $\vec{a} \cdot \vec{b}$ - скалярное произведение векторов, а $|\vec{a}|$ и $|\vec{b}|$ - их длины (модули).

Даны вершины треугольника: $A(1; 6)$, $B(-2; 3)$, $C(2; -1)$.

Косинус угла A

Угол A образован векторами $\vec{AB}$ и $\vec{AC}$.

1. Найдем координаты этих векторов:

$\vec{AB} = (x_B - x_A; y_B - y_A) = (-2 - 1; 3 - 6) = (-3; -3)$

$\vec{AC} = (x_C - x_A; y_C - y_A) = (2 - 1; -1 - 6) = (1; -7)$

2. Найдем длины (модули) векторов:

$|\vec{AB}| = \sqrt{(-3)^2 + (-3)^2} = \sqrt{9 + 9} = \sqrt{18} = 3\sqrt{2}$

$|\vec{AC}| = \sqrt{1^2 + (-7)^2} = \sqrt{1 + 49} = \sqrt{50} = 5\sqrt{2}$

3. Найдем скалярное произведение векторов:

$\vec{AB} \cdot \vec{AC} = (-3) \cdot 1 + (-3) \cdot (-7) = -3 + 21 = 18$

4. Вычислим косинус угла A:

$\cos(A) = \frac{\vec{AB} \cdot \vec{AC}}{|\vec{AB}| \cdot |\vec{AC}|} = \frac{18}{3\sqrt{2} \cdot 5\sqrt{2}} = \frac{18}{15 \cdot 2} = \frac{18}{30} = \frac{3}{5}$

Ответ: $\cos(A) = \frac{3}{5}$

Косинус угла B

Угол B образован векторами $\vec{BA}$ и $\vec{BC}$.

1. Найдем координаты этих векторов:

$\vec{BA} = (x_A - x_B; y_A - y_B) = (1 - (-2); 6 - 3) = (3; 3)$

$\vec{BC} = (x_C - x_B; y_C - y_B) = (2 - (-2); -1 - 3) = (4; -4)$

2. Найдем длины векторов:

$|\vec{BA}| = \sqrt{3^2 + 3^2} = \sqrt{9 + 9} = \sqrt{18} = 3\sqrt{2}$

$|\vec{BC}| = \sqrt{4^2 + (-4)^2} = \sqrt{16 + 16} = \sqrt{32} = 4\sqrt{2}$

3. Найдем скалярное произведение векторов:

$\vec{BA} \cdot \vec{BC} = 3 \cdot 4 + 3 \cdot (-4) = 12 - 12 = 0$

4. Вычислим косинус угла B:

$\cos(B) = \frac{\vec{BA} \cdot \vec{BC}}{|\vec{BA}| \cdot |\vec{BC}|} = \frac{0}{3\sqrt{2} \cdot 4\sqrt{2}} = 0$

Ответ: $\cos(B) = 0$

Косинус угла C

Угол C образован векторами $\vec{CA}$ и $\vec{CB}$.

1. Найдем координаты этих векторов:

$\vec{CA} = (x_A - x_C; y_A - y_C) = (1 - 2; 6 - (-1)) = (-1; 7)$

$\vec{CB} = (x_B - x_C; y_B - y_C) = (-2 - 2; 3 - (-1)) = (-4; 4)$

2. Найдем длины векторов:

$|\vec{CA}| = \sqrt{(-1)^2 + 7^2} = \sqrt{1 + 49} = \sqrt{50} = 5\sqrt{2}$

$|\vec{CB}| = \sqrt{(-4)^2 + 4^2} = \sqrt{16 + 16} = \sqrt{32} = 4\sqrt{2}$

3. Найдем скалярное произведение векторов:

$\vec{CA} \cdot \vec{CB} = (-1) \cdot (-4) + 7 \cdot 4 = 4 + 28 = 32$

4. Вычислим косинус угла C:

$\cos(C) = \frac{\vec{CA} \cdot \vec{CB}}{|\vec{CA}| \cdot |\vec{CB}|} = \frac{32}{5\sqrt{2} \cdot 4\sqrt{2}} = \frac{32}{20 \cdot 2} = \frac{32}{40} = \frac{4}{5}$

Ответ: $\cos(C) = \frac{4}{5}$

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