kalbim

Verified answer

Sin(x - π/2) = -sin(π/2 - x) = -cosx
√2*cos^2(x) = -cosx
√2*cos^2(x) + cosx = 0
cosx*(√2*cosx + 1) = 0
cosx = 0, x = π/2 + πk
cosx = -√2/2, x = +- 3π/4 + 2πk
указанному отрезку принадлежат два корня: -3π/2, -5π/4