What is cosx-2sinxcosx equals 0?

Answer 1

cos x - 2 sin x cos x = 0

-> cos x (1 - 2 sin x) = 0

=> cos x = 0 or 1 - 2 sin x = 0

cos x = 0:

x = π/2 + kπ

1 - 2 sin x = 0:

sin x = 1/2

-> x = π/6 + 2kπ or 5/6π + 2kπ

Thus

x = π/2 + kπ;

x = π/6 + 2kπ;

x = 5/6π + 2kπ

solve the original equation.