Решите уравнение - sinx/2=cosx

-sin (x/2) = cos x = 1 - 2sin^2 (x/2)

Замена sin (x/2) = y

2y^2 - y - 1 = 0

(y - 1) (2y + 1) = 0

y1 = sin (x/2) = - 1/2

x/2 = - pi/6 + 2pi*k; x1 = - pi/3 + 4pi*k

x/2 = - 5pi/6 + 2pi*k; x2 = - 5pi/3 + 4pi*k

y2 = sin (x/2) = 1

x3 = pi/2 + 2pi*n