Question

5 cos^2 α- 4, если sin^2 α=0,4​

Answer 1

Ответ:

решение смотри на фотографии

Объяснение:

Answer 2

To find the value of the expression 5cos²α - 4 given sin²α = 0.4, we can use the trigonometric identity:

sin²α + cos²α = 1.

Rearranging the identity, we have:

cos²α = 1 - sin²α.

Substituting sin²α = 0.4 into the equation, we get:

cos²α = 1 - 0.4 cos²α = 0.6.

Now, we can substitute this value of cos²α back into the original expression:

5cos²α - 4 = 5(0.6) - 4 = 3 - 4 = -1.

Therefore, the value of the expression 5cos²α - 4, when sin²α = 0.4, is -1.