Question

Найти 7cos2a, если sina = -0,2

Answer 1

Ответ:6.72

Пошаговое объяснение:

Answer 2

To find the value of 7cos(2a) given that sin(a) = -0.2, we can use the trigonometric identity:

cos(2a) = 1 - 2sin^2(a)

We already know that sin(a) = -0.2, so we can substitute this value into the identity:

cos(2a) = 1 - 2(-0.2)^2 cos(2a) = 1 - 2(0.04) cos(2a) = 1 - 0.08 cos(2a) = 0.92

Now, to find 7cos(2a), we simply multiply the value of cos(2a) by 7:

7cos(2a) = 7 * 0.92 7cos(2a) = 6.44

Therefore, the value of 7cos(2a) when sin(a) = -0.2 is 6.44.