2sinx-sin*квадрат*x=cos*квадрат*x, tg*квадрат*x+tgx=0.

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

2sin(x) - sin(x) - 1 + sin(x) = 0

sin(x) = 1/2

x = (-1)ᵏ(π/6) + πk, k - целое.

2) tg(x) + tg(x) = 0

tg(x) = 0 --> x = πk

tg(x) = -1 --> x = -π/4 + πk

k - целое.