Номер 716, страница 206 - гдз по алгебре 9 класс учебник Солтан, Солтан
Авторы: Солтан Г. Н., Солтан А. Е., Жумадилова А. Ж.
Тип: Учебник
Издательство: Кокшетау
Год издания: 2019 - 2026
ISBN: 978-601-317-424-2
Рекомендовано Министерством образования и науки Республики Казахстан
Популярные ГДЗ в 9 классе
IV. Тригонометрия. 27. Формулы тригонометрических функций двойного и половинного углов - номер 716, страница 206.
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" => 1108457 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "206" "field_page_end" => null "field_url" => "/9-klass/algebra/kokshetau-soltan-uchebnik/1-716" "field_display_title" => "716" "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: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #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 {#1071 #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" => 1107662 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_display_title" => "IV. 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"field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1064 …2} "field_new_book" => Illuminate\Database\Eloquent\Collection {#1065 …2} "field_old_book" => Illuminate\Database\Eloquent\Collection {#1066 …2} "field_url" => "/9-klass/algebra/kokshetau-soltan-uchebnik" "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1067 …2} "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "breadcrumbs" => array:3 [ …3] ] #original: array:50 [ "id" => 4298 "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 {#1041 …2} "field_class" => Illuminate\Database\Eloquent\Collection {#1043 …2} "field_publisher" => Illuminate\Database\Eloquent\Collection {#1045 …2} "field_author" => Illuminate\Database\Eloquent\Collection {#1047 …2} 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"field_description_top" => null "field_description_bottom" => null "breadcrumbs" => array:3 [ …3] ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "branch_parent" => Illuminate\Database\Eloquent\Collection {#1068 #items: [] #escapeWhenCastingToString: false } ] #original: array:24 [ "id" => 1107662 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_display_title" => "IV. 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"field_description_top" => null "field_description_bottom" => null "breadcrumbs" => array:3 [ …3] ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "branch_parent" => Illuminate\Database\Eloquent\Collection {#1101 #items: [] #escapeWhenCastingToString: false } ] #original: array:24 [ "id" => 1107662 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_display_title" => "IV. 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+wasRecentlyCreated: false #escapeWhenCastingToString: false #attributes: array:50 [ "id" => 4298 "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 {#1106 …2} "field_class" => Illuminate\Database\Eloquent\Collection {#1108 …2} "field_publisher" => Illuminate\Database\Eloquent\Collection {#1110 …2} "field_author" => Illuminate\Database\Eloquent\Collection {#1112 …2} "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1116 …2} "field_book_type" => Illuminate\Database\Eloquent\Collection {#1117 …2} "field_country" => Illuminate\Database\Eloquent\Collection {#1119 …2} "field_city" => Illuminate\Database\Eloquent\Collection {#1121 …2} "field_series" => Illuminate\Database\Eloquent\Collection {#1123 …2} "field_umk" => Illuminate\Database\Eloquent\Collection {#1124 …2} "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1125 …2} "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1126 …2} "field_publication_number" => null "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1127 …2} "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1128 …2} "field_under_the_edition_degree" => null "field_cover_description" => null "field_publication_year" => "2019" "field_publication_year_until" => null "field_part" => "" "field_part_writing" => "" "field_second_foreign_language" => null "field_for_whom" => "Учебник для учащихся 9 класса общеобразовательных школ" "field_allowed" => "Рекомендовано Министерством образования и науки Республики Казахстан" "field_reserve_field" => null "field_link_to_source" => null "field_tasks_count" => "1291" "field_priority" => "4" "field_default_folder" => "/algebra_09/soltan-u19/" "field_isbn" => "978-601-317-424-2" "field_cover" => array:1 [ …1] "field_cover_alts" => array:1 [ …1] "field_covers" => array:1 [ …1] "field_popular_book" => null "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1129 …2} "field_new_book" => Illuminate\Database\Eloquent\Collection {#1130 …2} "field_old_book" => Illuminate\Database\Eloquent\Collection {#1131 …2} "field_url" => "/9-klass/algebra/kokshetau-soltan-uchebnik" "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1132 …2} "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "breadcrumbs" => array:3 [ …3] ] #original: array:50 [ "id" => 4298 "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 {#1106 …2} "field_class" => Illuminate\Database\Eloquent\Collection {#1108 …2} "field_publisher" => Illuminate\Database\Eloquent\Collection {#1110 …2} "field_author" => Illuminate\Database\Eloquent\Collection {#1112 …2} "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1116 …2} "field_book_type" => Illuminate\Database\Eloquent\Collection {#1117 …2} "field_country" => Illuminate\Database\Eloquent\Collection {#1119 …2} "field_city" => Illuminate\Database\Eloquent\Collection {#1121 …2} "field_series" => Illuminate\Database\Eloquent\Collection {#1123 …2} "field_umk" => Illuminate\Database\Eloquent\Collection {#1124 …2} "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1125 …2} "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1126 …2} "field_publication_number" => null "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1127 …2} "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1128 …2} "field_under_the_edition_degree" => null "field_cover_description" => null "field_publication_year" => "2019" "field_publication_year_until" => null "field_part" => "" "field_part_writing" => "" "field_second_foreign_language" => null "field_for_whom" => "Учебник для учащихся 9 класса общеобразовательных школ" "field_allowed" => "Рекомендовано Министерством образования и науки Республики Казахстан" "field_reserve_field" => null "field_link_to_source" => null "field_tasks_count" => "1291" "field_priority" => "4" "field_default_folder" => "/algebra_09/soltan-u19/" "field_isbn" => "978-601-317-424-2" "field_cover" => array:1 [ …1] "field_cover_alts" => array:1 [ …1] "field_covers" => array:1 [ …1] "field_popular_book" => null "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1129 …2} "field_new_book" => Illuminate\Database\Eloquent\Collection {#1130 …2} "field_old_book" => Illuminate\Database\Eloquent\Collection {#1131 …2} "field_url" => "/9-klass/algebra/kokshetau-soltan-uchebnik" "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1132 …2} "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "breadcrumbs" => array:3 [ …3] ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "branch_parent" => Illuminate\Database\Eloquent\Collection {#1133 #items: array:1 [ 0 => App\Models\Branch {#1134 #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" => 1107662 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_display_title" => "IV. Тригонометрия" "field_branch_order" => null "field_url" => null "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1135 …2} "field_page_start" => "147" "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 {#1136 …2} "branch_parent" => Illuminate\Database\Eloquent\Collection {#1165 …2} ] #original: array:24 [ "id" => 1107662 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_display_title" => "IV. Тригонометрия" "field_branch_order" => null "field_url" => null "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1135 …2} "field_page_start" => "147" "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 {#1136 …2} "branch_parent" => Illuminate\Database\Eloquent\Collection {#1165 …2} ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } ] #original: array:24 [ "id" => 1107669 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_display_title" => "27. Формулы тригонометрических функций двойного и половинного углов" "field_branch_order" => null "field_url" => null "field_branch_type" => Illuminate\Database\Eloquent\Collection {#1103} "field_page_start" => "203" "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 {#1104} "branch_parent" => Illuminate\Database\Eloquent\Collection {#1133} ] #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 {#1192 #items: array:3 [ 0 => App\Models\Element {#1168 #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" => 1277071 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "edition" => Illuminate\Database\Eloquent\Collection {#1169 #items: array:1 [ 0 => App\Models\Edition {#1167 #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 [ "id" => 4953 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "title" => "Условие" "field_order" => "1" "field_publisher" => Illuminate\Database\Eloquent\Collection {#1170 …2} "field_content_type" => "free" "field_content_mode" => "text, image" "field_page_content_mode" => "image" "field_content_text_checked" => null "field_page_content_text_checked" => "0" "field_solution_author" => "Автор" "field_moderator" => "pasha" "field_edition_type" => "statement" "field_root_dir" => "0-" "field_responsible" => Illuminate\Database\Eloquent\Collection {#1172 …2} "field_comment" => null "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1173 …2} "field_process_formula" => "katex" "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1174 …2} "field_content_source" => null ] #original: array:21 [ "id" => 4953 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "title" => "Условие" "field_order" => "1" "field_publisher" => Illuminate\Database\Eloquent\Collection {#1170 …2} "field_content_type" => "free" "field_content_mode" => "text, image" "field_page_content_mode" => "image" "field_content_text_checked" => null "field_page_content_text_checked" => "0" "field_solution_author" => "Автор" "field_moderator" => "pasha" "field_edition_type" => "statement" "field_root_dir" => "0-" "field_responsible" => Illuminate\Database\Eloquent\Collection {#1172 …2} "field_comment" => null "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1173 …2} "field_process_formula" => "katex" "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1174 …2} "field_content_source" => null ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "task" => array:2 [ "refs" => "1108457" "type" => "task" ] "text" => "<p><strong>716. a)</strong> В равнобедренном треугольнике синус угла при основании равен $\frac{7}{25}$. Найдите синус и косинус угла при его вершине.</p><p><strong>б)</strong> Известно, что в ромбе <em>ABCD</em> $\cos \angle CAD = 0,2$. Найдите косинус угла <em>BAD</em> и установите, тупым или острым является этот угол.</p>" "img" => array:1 [ 0 => array:5 [ "name" => "716-1.jpg" "alt" => null "width" => "1582" "height" => 445 "path" => "/media/algebra_09/soltan-u19/0-1/716-1.webp?ts=1752834710" ] ] ] #original: array:7 [ "id" => 1277071 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "edition" => Illuminate\Database\Eloquent\Collection {#1169} "task" => array:2 [ "refs" => "1108457" "type" => "task" ] "text" => "<p><strong>716. a)</strong> В равнобедренном треугольнике синус угла при основании равен $\frac{7}{25}$. Найдите синус и косинус угла при его вершине.</p><p><strong>б)</strong> Известно, что в ромбе <em>ABCD</em> $\cos \angle CAD = 0,2$. Найдите косинус угла <em>BAD</em> и установите, тупым или острым является этот угол.</p>" "img" => array:1 [ 0 => array:5 [ "name" => "716-1.jpg" "alt" => null "width" => "1582" "height" => 445 "path" => "/media/algebra_09/soltan-u19/0-1/716-1.webp?ts=1752834710" ] ] ] #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 {#1175 #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" => 1278362 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "edition" => Illuminate\Database\Eloquent\Collection {#1176 #items: array:1 [ 0 => App\Models\Edition {#1177 #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 [ "id" => 4954 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "title" => "Решение" "field_order" => "2" "field_publisher" => Illuminate\Database\Eloquent\Collection {#1178 …2} "field_content_type" => "free" "field_content_mode" => "image" "field_page_content_mode" => "" "field_content_text_checked" => "0" "field_page_content_text_checked" => "0" "field_solution_author" => "Неизвестный" "field_moderator" => "pasha" "field_edition_type" => "solution" "field_root_dir" => "1-" "field_responsible" => Illuminate\Database\Eloquent\Collection {#1180 …2} "field_comment" => null "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1181 …2} "field_process_formula" => "" "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1182 …2} "field_content_source" => null ] #original: array:21 [ "id" => 4954 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "title" => "Решение" "field_order" => "2" "field_publisher" => Illuminate\Database\Eloquent\Collection {#1178 …2} "field_content_type" => "free" "field_content_mode" => "image" "field_page_content_mode" => "" "field_content_text_checked" => "0" "field_page_content_text_checked" => "0" "field_solution_author" => "Неизвестный" "field_moderator" => "pasha" "field_edition_type" => "solution" "field_root_dir" => "1-" "field_responsible" => Illuminate\Database\Eloquent\Collection {#1180 …2} "field_comment" => null "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1181 …2} "field_process_formula" => "" "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1182 …2} "field_content_source" => null ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "task" => array:2 [ "refs" => "1108457" "type" => "task" ] "img" => array:1 [ 0 => array:5 [ "name" => "716-1.jpg" "alt" => null "width" => "1385" "height" => 1675 "path" => "/media/algebra_09/soltan-u19/1-1/716-1.webp?ts=1752831506" ] ] ] #original: array:6 [ "id" => 1278362 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "edition" => Illuminate\Database\Eloquent\Collection {#1176} "task" => array:2 [ "refs" => "1108457" "type" => "task" ] "img" => array:1 [ 0 => array:5 [ "name" => "716-1.jpg" "alt" => null "width" => "1385" "height" => 1675 "path" => "/media/algebra_09/soltan-u19/1-1/716-1.webp?ts=1752831506" ] ] ] #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 {#1183 #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" => 1554317 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "edition" => Illuminate\Database\Eloquent\Collection {#1184 #items: array:1 [ 0 => App\Models\Edition {#1185 #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 [ "id" => 5665 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "title" => "Решение 2 (rus)" "field_order" => "3" "field_publisher" => Illuminate\Database\Eloquent\Collection {#1186 …2} "field_content_type" => "free" "field_content_mode" => "text" "field_page_content_mode" => "" "field_content_text_checked" => null "field_page_content_text_checked" => "0" "field_solution_author" => "Gemini 2.5 Pro" "field_moderator" => "tolik" "field_edition_type" => "solution" "field_root_dir" => "2-" "field_responsible" => Illuminate\Database\Eloquent\Collection {#1188 …2} "field_comment" => null "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1189 …2} "field_process_formula" => "katex" "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1190 …2} "field_content_source" => null ] #original: array:21 [ "id" => 5665 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "title" => "Решение 2 (rus)" "field_order" => "3" "field_publisher" => Illuminate\Database\Eloquent\Collection {#1186 …2} "field_content_type" => "free" "field_content_mode" => "text" "field_page_content_mode" => "" "field_content_text_checked" => null "field_page_content_text_checked" => "0" "field_solution_author" => "Gemini 2.5 Pro" "field_moderator" => "tolik" "field_edition_type" => "solution" "field_root_dir" => "2-" "field_responsible" => Illuminate\Database\Eloquent\Collection {#1188 …2} "field_comment" => null "field_similar_book" => Illuminate\Database\Eloquent\Collection {#1189 …2} "field_process_formula" => "katex" "field_edition_group" => Illuminate\Database\Eloquent\Collection {#1190 …2} "field_content_source" => null ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "task" => array:2 [ "refs" => "1108457" "type" => "task" ] "text" => "<p><strong>а)</strong> Пусть в равнобедренном треугольнике угол при основании равен $\alpha$, а угол при вершине равен $\beta$. По условию задачи, $\sin \alpha = \frac{7}{25}$. Сумма углов в треугольнике равна $180^\circ$, поэтому $2\alpha + \beta = 180^\circ$. Отсюда следует, что угол при вершине $\beta = 180^\circ - 2\alpha$.Чтобы найти синус и косинус угла $\beta$, воспользуемся формулами приведения: $\sin \beta = \sin(180^\circ - 2\alpha) = \sin(2\alpha)$ и $\cos \beta = \cos(180^\circ - 2\alpha) = -\cos(2\alpha)$.Для вычисления $\sin(2\alpha)$ и $\cos(2\alpha)$ сначала найдем $\cos \alpha$ из основного тригонометрического тождества $\sin^2 \alpha + \cos^2 \alpha = 1$.$\cos^2 \alpha = 1 - \sin^2 \alpha = 1 - \left(\frac{7}{25}\right)^2 = 1 - \frac{49}{625} = \frac{625 - 49}{625} = \frac{576}{625}$.Так как $\alpha$ — это угол при основании равнобедренного треугольника, он не может быть тупым ($2\alpha < 180^\circ \Rightarrow \alpha < 90^\circ$), значит, его косинус положителен.Следовательно, $\cos \alpha = \sqrt{\frac{576}{625}} = \frac{24}{25}$.Теперь, используя формулы двойного угла, находим:$\sin(2\alpha) = 2 \sin \alpha \cos \alpha = 2 \cdot \frac{7}{25} \cdot \frac{24}{25} = \frac{336}{625}$.$\cos(2\alpha) = \cos^2 \alpha - \sin^2 \alpha = \left(\frac{24}{25}\right)^2 - \left(\frac{7}{25}\right)^2 = \frac{576 - 49}{625} = \frac{527}{625}$.Наконец, вычисляем искомые значения для угла $\beta$:$\sin \beta = \sin(2\alpha) = \frac{336}{625}$.$\cos \beta = -\cos(2\alpha) = -\frac{527}{625}$.</p><p><strong>Ответ:</strong> синус угла при вершине равен $\frac{336}{625}$, косинус равен $-\frac{527}{625}$.</p><p><strong>б)</strong> В ромбе диагонали являются биссектрисами его углов. Следовательно, диагональ $AC$ делит угол $BAD$ пополам. Таким образом, $\angle BAD = 2 \cdot \angle CAD$.Нам дан косинус угла $CAD$: $\cos \angle CAD = 0,2$.Требуется найти косинус угла $BAD$. Для этого воспользуемся формулой косинуса двойного угла: $\cos(2x) = 2\cos^2 x - 1$.Подставим известное значение:$\cos \angle BAD = 2 \cdot (\cos \angle CAD)^2 - 1 = 2 \cdot (0,2)^2 - 1 = 2 \cdot 0,04 - 1 = 0,08 - 1 = -0,92$.Далее, установим, является ли угол $BAD$ тупым или острым. Тип угла определяется знаком его косинуса. Если косинус угла положителен, угол острый ($0^\circ < \alpha < 90^\circ$). Если косинус отрицателен, угол тупой ($90^\circ < \alpha < 180^\circ$).Поскольку $\cos \angle BAD = -0,92$, что является отрицательным числом, угол $BAD$ — тупой.</p><p><strong>Ответ:</strong> косинус угла $BAD$ равен $-0,92$; угол является тупым.</p>" ] #original: array:6 [ "id" => 1554317 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "edition" => Illuminate\Database\Eloquent\Collection {#1184} "task" => array:2 [ "refs" => "1108457" "type" => "task" ] "text" => "<p><strong>а)</strong> Пусть в равнобедренном треугольнике угол при основании равен $\alpha$, а угол при вершине равен $\beta$. По условию задачи, $\sin \alpha = \frac{7}{25}$. Сумма углов в треугольнике равна $180^\circ$, поэтому $2\alpha + \beta = 180^\circ$. Отсюда следует, что угол при вершине $\beta = 180^\circ - 2\alpha$.Чтобы найти синус и косинус угла $\beta$, воспользуемся формулами приведения: $\sin \beta = \sin(180^\circ - 2\alpha) = \sin(2\alpha)$ и $\cos \beta = \cos(180^\circ - 2\alpha) = -\cos(2\alpha)$.Для вычисления $\sin(2\alpha)$ и $\cos(2\alpha)$ сначала найдем $\cos \alpha$ из основного тригонометрического тождества $\sin^2 \alpha + \cos^2 \alpha = 1$.$\cos^2 \alpha = 1 - \sin^2 \alpha = 1 - \left(\frac{7}{25}\right)^2 = 1 - \frac{49}{625} = \frac{625 - 49}{625} = \frac{576}{625}$.Так как $\alpha$ — это угол при основании равнобедренного треугольника, он не может быть тупым ($2\alpha < 180^\circ \Rightarrow \alpha < 90^\circ$), значит, его косинус положителен.Следовательно, $\cos \alpha = \sqrt{\frac{576}{625}} = \frac{24}{25}$.Теперь, используя формулы двойного угла, находим:$\sin(2\alpha) = 2 \sin \alpha \cos \alpha = 2 \cdot \frac{7}{25} \cdot \frac{24}{25} = \frac{336}{625}$.$\cos(2\alpha) = \cos^2 \alpha - \sin^2 \alpha = \left(\frac{24}{25}\right)^2 - \left(\frac{7}{25}\right)^2 = \frac{576 - 49}{625} = \frac{527}{625}$.Наконец, вычисляем искомые значения для угла $\beta$:$\sin \beta = \sin(2\alpha) = \frac{336}{625}$.$\cos \beta = -\cos(2\alpha) = -\frac{527}{625}$.</p><p><strong>Ответ:</strong> синус угла при вершине равен $\frac{336}{625}$, косинус равен $-\frac{527}{625}$.</p><p><strong>б)</strong> В ромбе диагонали являются биссектрисами его углов. Следовательно, диагональ $AC$ делит угол $BAD$ пополам. Таким образом, $\angle BAD = 2 \cdot \angle CAD$.Нам дан косинус угла $CAD$: $\cos \angle CAD = 0,2$.Требуется найти косинус угла $BAD$. Для этого воспользуемся формулой косинуса двойного угла: $\cos(2x) = 2\cos^2 x - 1$.Подставим известное значение:$\cos \angle BAD = 2 \cdot (\cos \angle CAD)^2 - 1 = 2 \cdot (0,2)^2 - 1 = 2 \cdot 0,04 - 1 = 0,08 - 1 = -0,92$.Далее, установим, является ли угол $BAD$ тупым или острым. Тип угла определяется знаком его косинуса. Если косинус угла положителен, угол острый ($0^\circ < \alpha < 90^\circ$). Если косинус отрицателен, угол тупой ($90^\circ < \alpha < 180^\circ$).Поскольку $\cos \angle BAD = -0,92$, что является отрицательным числом, угол $BAD$ — тупой.</p><p><strong>Ответ:</strong> косинус угла $BAD$ равен $-0,92$; угол является тупым.</p>" ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "next" => array:2 [ "refs" => "1108458" "type" => "task" ] "previous" => array:2 [ "refs" => "1108456" "type" => "task" ] "book" => Illuminate\Database\Eloquent\Collection {#1222 #items: array:1 [ 0 => App\Models\Book {#1193 #connection: "mysql" #table: "books" #primaryKey: "id" #keyType: "int" +incrementing: false #with: [] #withCount: [] +preventsLazyLoading: false #perPage: 15 +exists: true +wasRecentlyCreated: false 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=> Illuminate\Database\Eloquent\Collection {#1219 #items: [] #escapeWhenCastingToString: false } "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "breadcrumbs" => array:3 [ "class" => 380 "subject" => 542 "class_subject" => 386 ] ] #original: array:50 [ "id" => 4298 "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 {#1194} "field_class" => Illuminate\Database\Eloquent\Collection {#1195} "field_publisher" => Illuminate\Database\Eloquent\Collection {#1197} "field_author" => Illuminate\Database\Eloquent\Collection {#1199} "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1203} "field_book_type" => Illuminate\Database\Eloquent\Collection {#1204} "field_country" => Illuminate\Database\Eloquent\Collection {#1206} "field_city" => Illuminate\Database\Eloquent\Collection {#1208} "field_series" => Illuminate\Database\Eloquent\Collection {#1210} "field_umk" => Illuminate\Database\Eloquent\Collection {#1211} "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1212} "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1213} "field_publication_number" => null "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1214} "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1215} "field_under_the_edition_degree" => null "field_cover_description" => null "field_publication_year" => "2019" "field_publication_year_until" => null "field_part" => "" "field_part_writing" => "" "field_second_foreign_language" => null "field_for_whom" => "Учебник для учащихся 9 класса общеобразовательных школ" "field_allowed" => "Рекомендовано Министерством образования и науки Республики Казахстан" "field_reserve_field" => null "field_link_to_source" => null "field_tasks_count" => "1291" "field_priority" => "4" "field_default_folder" => "/algebra_09/soltan-u19/" "field_isbn" => "978-601-317-424-2" "field_cover" => array:1 [ 0 => "/media/algebra_09/soltan-u19/covers/cover1.webp?ts=1752140452" ] "field_cover_alts" => array:1 [ 0 => "" ] "field_covers" => array:1 [ 0 => array:4 [ "path" => "/media/algebra_09/soltan-u19/covers/cover1.webp?ts=1752140452" "alt" => "" "width" => "1940" "height" => "2895" ] ] "field_popular_book" => null "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1216} "field_new_book" => Illuminate\Database\Eloquent\Collection {#1217} "field_old_book" => Illuminate\Database\Eloquent\Collection {#1218} "field_url" => "/9-klass/algebra/kokshetau-soltan-uchebnik" "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1219} "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "breadcrumbs" => array:3 [ "class" => 380 "subject" => 542 "class_subject" => 386 ] ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "page" => Illuminate\Database\Eloquent\Collection {#1862 #items: array:1 [ 0 => App\Models\BookPage {#1032 #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" => 1097948 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "206" "field_url" => "/9-klass/algebra/kokshetau-soltan-uchebnik/page-206" "field_display_title" => "206" "field_folder" => "folder1" "field_image_name" => "206" "field_branch_parent" => Illuminate\Database\Eloquent\Collection {#1023 #items: [] #escapeWhenCastingToString: false } "field_weight" => "0" "field_book_parent" => Illuminate\Database\Eloquent\Collection {#1026 #items: array:1 [ 0 => App\Models\Book {#1220 #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" => 4298 "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 {#1221 …2} "field_class" => Illuminate\Database\Eloquent\Collection {#1224 …2} "field_publisher" => Illuminate\Database\Eloquent\Collection {#1226 …2} "field_author" => Illuminate\Database\Eloquent\Collection {#1228 …2} "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1232 …2} "field_book_type" => Illuminate\Database\Eloquent\Collection {#1233 …2} "field_country" => Illuminate\Database\Eloquent\Collection {#1235 …2} "field_city" => Illuminate\Database\Eloquent\Collection {#1237 …2} "field_series" => Illuminate\Database\Eloquent\Collection {#1239 …2} "field_umk" => Illuminate\Database\Eloquent\Collection {#1240 …2} "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1241 …2} "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1242 …2} "field_publication_number" => null "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1243 …2} "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1244 …2} "field_under_the_edition_degree" => null "field_cover_description" => null "field_publication_year" => "2019" "field_publication_year_until" => null "field_part" => "" "field_part_writing" => "" "field_second_foreign_language" => null "field_for_whom" => "Учебник для учащихся 9 класса общеобразовательных школ" "field_allowed" => "Рекомендовано Министерством образования и науки Республики Казахстан" "field_reserve_field" => null "field_link_to_source" => null "field_tasks_count" => "1291" "field_priority" => "4" "field_default_folder" => "/algebra_09/soltan-u19/" "field_isbn" => "978-601-317-424-2" "field_cover" => array:1 [ …1] "field_cover_alts" => array:1 [ …1] "field_covers" => array:1 [ …1] "field_popular_book" => null "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1245 …2} "field_new_book" => Illuminate\Database\Eloquent\Collection {#1246 …2} "field_old_book" => Illuminate\Database\Eloquent\Collection {#1247 …2} "field_url" => "/9-klass/algebra/kokshetau-soltan-uchebnik" "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1248 …2} "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "breadcrumbs" => array:3 [ …3] ] #original: array:50 [ "id" => 4298 "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 {#1221 …2} "field_class" => Illuminate\Database\Eloquent\Collection {#1224 …2} "field_publisher" => Illuminate\Database\Eloquent\Collection {#1226 …2} "field_author" => Illuminate\Database\Eloquent\Collection {#1228 …2} "field_author_foreign" => Illuminate\Database\Eloquent\Collection {#1232 …2} "field_book_type" => Illuminate\Database\Eloquent\Collection {#1233 …2} "field_country" => Illuminate\Database\Eloquent\Collection {#1235 …2} "field_city" => Illuminate\Database\Eloquent\Collection {#1237 …2} "field_series" => Illuminate\Database\Eloquent\Collection {#1239 …2} "field_umk" => Illuminate\Database\Eloquent\Collection {#1240 …2} "field_level_of_education" => Illuminate\Database\Eloquent\Collection {#1241 …2} "field_standart_of_education" => Illuminate\Database\Eloquent\Collection {#1242 …2} "field_publication_number" => null "field_publication_type" => Illuminate\Database\Eloquent\Collection {#1243 …2} "field_under_the_edition" => Illuminate\Database\Eloquent\Collection {#1244 …2} "field_under_the_edition_degree" => null "field_cover_description" => null "field_publication_year" => "2019" "field_publication_year_until" => null "field_part" => "" "field_part_writing" => "" "field_second_foreign_language" => null "field_for_whom" => "Учебник для учащихся 9 класса общеобразовательных школ" "field_allowed" => "Рекомендовано Министерством образования и науки Республики Казахстан" "field_reserve_field" => null "field_link_to_source" => null "field_tasks_count" => "1291" "field_priority" => "4" "field_default_folder" => "/algebra_09/soltan-u19/" "field_isbn" => "978-601-317-424-2" "field_cover" => array:1 [ …1] "field_cover_alts" => array:1 [ …1] "field_covers" => array:1 [ …1] "field_popular_book" => null "field_recommended_books" => Illuminate\Database\Eloquent\Collection {#1245 …2} "field_new_book" => Illuminate\Database\Eloquent\Collection {#1246 …2} "field_old_book" => Illuminate\Database\Eloquent\Collection {#1247 …2} "field_url" => "/9-klass/algebra/kokshetau-soltan-uchebnik" "field_cover_color" => Illuminate\Database\Eloquent\Collection {#1248 …2} "field_metatags_title" => null "field_metatags_description" => null "field_h1" => null "field_description_top" => null "field_description_bottom" => null "breadcrumbs" => array:3 [ …3] ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #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 "edition_groups" => Illuminate\Database\Eloquent\Collection {#1249 #items: [] #escapeWhenCastingToString: false } "content" => Illuminate\Database\Eloquent\Collection {#1250 #items: array:1 [ 0 => App\Models\Element {#1251 #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" => 1261099 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "edition" => Illuminate\Database\Eloquent\Collection {#1252 …2} "book_page" => array:2 [ …2] "img" => array:1 [ …1] ] #original: array:6 [ "id" => 1261099 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "edition" => Illuminate\Database\Eloquent\Collection {#1252 …2} "book_page" => array:2 [ …2] "img" => array:1 [ …1] ] #changes: [] #casts: [] #classCastCache: [] #attributeCastCache: [] #dateFormat: null #appends: [] #dispatchesEvents: [] #observables: [] #relations: [] #touches: [] +timestamps: true +usesUniqueIds: false #hidden: [] #visible: [] #fillable: [] #guarded: array:1 [ 0 => "*" ] } ] #escapeWhenCastingToString: false } "next" => array:2 [ "refs" => "1097949" "type" => "book_page" ] "previous" => array:2 [ "refs" => "1097947" "type" => "book_page" ] "tasks" => Illuminate\Database\Eloquent\Collection {#1259 #items: array:6 [ 0 => App\Models\Task {#1260 #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" => 1108456 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "206" "field_page_end" => null "field_url" => "/9-klass/algebra/kokshetau-soltan-uchebnik/1-715" "field_display_title" => "715" "field_outside_task" => null "field_task_type" => Illuminate\Database\Eloquent\Collection {#1261 …2} "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 {#1263 …2} "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1264 …2} "parent_branches" => Illuminate\Database\Eloquent\Collection {#1297 …2} "content" => Illuminate\Database\Eloquent\Collection {#1334 …2} "next" => array:2 [ …2] "previous" => array:2 [ …2] "book" => Illuminate\Database\Eloquent\Collection {#1359 …2} "page" => array:2 [ …2] ] #original: array:24 [ "id" => 1108456 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "206" "field_page_end" => null "field_url" => "/9-klass/algebra/kokshetau-soltan-uchebnik/1-715" "field_display_title" => "715" "field_outside_task" => null "field_task_type" => Illuminate\Database\Eloquent\Collection {#1261 …2} "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 {#1263 …2} "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1264 …2} "parent_branches" => Illuminate\Database\Eloquent\Collection {#1297 …2} "content" => Illuminate\Database\Eloquent\Collection {#1334 …2} "next" => array:2 [ …2] "previous" => array:2 [ …2] "book" => Illuminate\Database\Eloquent\Collection {#1359 …2} "page" => array:2 [ …2] ] #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\Task {#1360 #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" => 1108457 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "206" "field_page_end" => null "field_url" => "/9-klass/algebra/kokshetau-soltan-uchebnik/1-716" "field_display_title" => "716" "field_outside_task" => null "field_task_type" => Illuminate\Database\Eloquent\Collection {#1361 …2} "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 {#1363 …2} "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1364 …2} "parent_branches" => Illuminate\Database\Eloquent\Collection {#1397 …2} "content" => Illuminate\Database\Eloquent\Collection {#1434 …2} "next" => array:2 [ …2] "previous" => array:2 [ …2] "book" => Illuminate\Database\Eloquent\Collection {#1459 …2} "page" => array:2 [ …2] ] #original: array:24 [ "id" => 1108457 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "206" "field_page_end" => null "field_url" => "/9-klass/algebra/kokshetau-soltan-uchebnik/1-716" "field_display_title" => "716" "field_outside_task" => null "field_task_type" => Illuminate\Database\Eloquent\Collection {#1361 …2} "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 {#1363 …2} "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1364 …2} "parent_branches" => Illuminate\Database\Eloquent\Collection {#1397 …2} "content" => Illuminate\Database\Eloquent\Collection {#1434 …2} "next" => array:2 [ …2] "previous" => array:2 [ …2] "book" => Illuminate\Database\Eloquent\Collection {#1459 …2} "page" => array:2 [ …2] ] #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\Task {#1460 #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" => 1108458 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "206" "field_page_end" => null "field_url" => "/9-klass/algebra/kokshetau-soltan-uchebnik/1-717" "field_display_title" => "717" "field_outside_task" => null "field_task_type" => Illuminate\Database\Eloquent\Collection {#1461 …2} "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 {#1463 …2} "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1464 …2} "parent_branches" => Illuminate\Database\Eloquent\Collection {#1497 …2} "content" => Illuminate\Database\Eloquent\Collection {#1534 …2} "next" => array:2 [ …2] "previous" => array:2 [ …2] "book" => Illuminate\Database\Eloquent\Collection {#1559 …2} "page" => array:2 [ …2] ] #original: array:24 [ "id" => 1108458 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "206" "field_page_end" => null "field_url" => "/9-klass/algebra/kokshetau-soltan-uchebnik/1-717" "field_display_title" => "717" "field_outside_task" => null "field_task_type" => Illuminate\Database\Eloquent\Collection {#1461 …2} "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 {#1463 …2} "top_parent_branch" => Illuminate\Database\Eloquent\Collection {#1464 …2} "parent_branches" => Illuminate\Database\Eloquent\Collection {#1497 …2} "content" => Illuminate\Database\Eloquent\Collection {#1534 …2} "next" => array:2 [ …2] "previous" => array:2 [ …2] "book" => Illuminate\Database\Eloquent\Collection {#1559 …2} "page" => array:2 [ …2] ] #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\Task {#1560 #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" => 1108459 "created_at" => "2026-04-10 13:58:26" …22 ] #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] } 4 => App\Models\Task {#1660 #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 {#1760 #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] } ] #escapeWhenCastingToString: false } ] #original: array:21 [ "id" => 1097948 "created_at" => "2026-04-10 13:58:26" "updated_at" => null "field_page_start" => "206" "field_url" => 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№716 (с. 206)
Условие. №716 (с. 206)
Решение 2 (rus). №716 (с. 206)
а) Пусть в равнобедренном треугольнике угол при основании равен $\alpha$, а угол при вершине равен $\beta$. По условию задачи, $\sin \alpha = \frac{7}{25}$. Сумма углов в треугольнике равна $180^\circ$, поэтому $2\alpha + \beta = 180^\circ$. Отсюда следует, что угол при вершине $\beta = 180^\circ - 2\alpha$.Чтобы найти синус и косинус угла $\beta$, воспользуемся формулами приведения: $\sin \beta = \sin(180^\circ - 2\alpha) = \sin(2\alpha)$ и $\cos \beta = \cos(180^\circ - 2\alpha) = -\cos(2\alpha)$.Для вычисления $\sin(2\alpha)$ и $\cos(2\alpha)$ сначала найдем $\cos \alpha$ из основного тригонометрического тождества $\sin^2 \alpha + \cos^2 \alpha = 1$.$\cos^2 \alpha = 1 - \sin^2 \alpha = 1 - \left(\frac{7}{25}\right)^2 = 1 - \frac{49}{625} = \frac{625 - 49}{625} = \frac{576}{625}$.Так как $\alpha$ — это угол при основании равнобедренного треугольника, он не может быть тупым ($2\alpha < 180^\circ \Rightarrow \alpha < 90^\circ$), значит, его косинус положителен.Следовательно, $\cos \alpha = \sqrt{\frac{576}{625}} = \frac{24}{25}$.Теперь, используя формулы двойного угла, находим:$\sin(2\alpha) = 2 \sin \alpha \cos \alpha = 2 \cdot \frac{7}{25} \cdot \frac{24}{25} = \frac{336}{625}$.$\cos(2\alpha) = \cos^2 \alpha - \sin^2 \alpha = \left(\frac{24}{25}\right)^2 - \left(\frac{7}{25}\right)^2 = \frac{576 - 49}{625} = \frac{527}{625}$.Наконец, вычисляем искомые значения для угла $\beta$:$\sin \beta = \sin(2\alpha) = \frac{336}{625}$.$\cos \beta = -\cos(2\alpha) = -\frac{527}{625}$.
Ответ: синус угла при вершине равен $\frac{336}{625}$, косинус равен $-\frac{527}{625}$.
б) В ромбе диагонали являются биссектрисами его углов. Следовательно, диагональ $AC$ делит угол $BAD$ пополам. Таким образом, $\angle BAD = 2 \cdot \angle CAD$.Нам дан косинус угла $CAD$: $\cos \angle CAD = 0,2$.Требуется найти косинус угла $BAD$. Для этого воспользуемся формулой косинуса двойного угла: $\cos(2x) = 2\cos^2 x - 1$.Подставим известное значение:$\cos \angle BAD = 2 \cdot (\cos \angle CAD)^2 - 1 = 2 \cdot (0,2)^2 - 1 = 2 \cdot 0,04 - 1 = 0,08 - 1 = -0,92$.Далее, установим, является ли угол $BAD$ тупым или острым. Тип угла определяется знаком его косинуса. Если косинус угла положителен, угол острый ($0^\circ < \alpha < 90^\circ$). Если косинус отрицателен, угол тупой ($90^\circ < \alpha < 180^\circ$).Поскольку $\cos \angle BAD = -0,92$, что является отрицательным числом, угол $BAD$ — тупой.
Ответ: косинус угла $BAD$ равен $-0,92$; угол является тупым.
Другие задания:
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