Решить уравнение

2cos^ 2x+sin2x-1=0

2cos^2 x - 1 = cos 2x

cos 2x + sin 2x = 0

√2 * (cos 2x*1/√2 + sin 2x*1/√2) = 0

√2 * (sin (pi/4) * cos (2x) + cos (pi/4) * sin (2x)) = 0

√2*sin (2x + pi/4) = 0

2x + pi/4 = pi*k

x = - pi/8 + pi/2*k