Ответы на вопрос:
Cos(α + β) = cosαcosβ - sinαsinβ
{cosα + cosβ = -4/5
{sinα + sinβ = 1/3
⬇️
{cos²α + 2cosαcosβ + cos²β = 16/25
{sin²α + 2sinαsinβ + sin²β = 1/9
+
1 + 2(cosαcosβ + sinαsinβ) + 1 = 16/25 + 1/9
2cos(α - β) = - 281/225
cos(α - β) = -281/450
{cosα + cosβ = -4/5
{sinα + sinβ = 1/3
⬇️
{cos²α + 2cosαcosβ + cos²β = 16/25
{sin²α + 2sinαsinβ + sin²β = 1/9
+
1 + 2(cosαcosβ + sinαsinβ) + 1 = 16/25 + 1/9
2cos(α - β) = - 281/225
cos(α - β) = -281/450
Популярно: Алгебра
-
kseniyarigil13.02.2022 05:47
-
ДмитрийYT24.10.2022 18:57
-
viktoriaedel05.06.2023 15:13
-
botikalmas08.05.2022 22:55
-
Dorefi23.01.2023 17:42
-
Алёна11Кот14.04.2022 20:52
-
vaxyl30.07.2020 17:05
-
Sonyavishnya09.06.2020 22:04
-
Локи3011.03.2022 01:19
-
Атлант2112.01.2020 17:49