Предмет: Алгебра, автор: Аноним

Найдите Sin A и Tg A, если Cos A = 2/7

Ответы

Автор ответа: Аноним

3

cos A = 2/7 0 < A < π/2 (I четверть)
sin^2 A = 1 - cos^2 A = 1 - (2/7)^2 = 1 - 4/49 = 45/49 => cos √45/√49 = 3√5/7
tg A = sin A/cos A = 3√5 · 2 / 7 · 7 = 6√5/49

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