cos^2x-sin(1,5п+x)=0

Решение
Cos²x - sin(3π/2 + x) = 0
cos²x + cosx = 0
cosx*(cosx + 1) = 0
1)  cosx = 0
x₁ = π/2 + πk, k ∈ Z
2) cosx + 1 = 0
 cosx = - 1
x₂ = π + 2πn, n ∈ Z
Ответ:  x₁ = π/2 + πk, k ∈ Z ; x₂ = π + 2πn, n ∈ Z