Question

Упростить выражение: cos^2(a+90)

Answer 1

cos²(α + 90°) = sin²α.

Answer 2

To simplify the expression cos^2(a + 90), we can use the trigonometric identity:

cos(x + 90°) = -sin(x)

Therefore,

cos^2(a + 90°) = (-sin(a))^2

And since the square of a negative value is positive, we get:

cos^2(a + 90°) = sin^2(a)

So the simplified expression is sin^2(a).