СЖ
Степан Жидик
sin2x+4sinxcosx+3cos2x = 0
sin2x+2sin2x + 3 cos2x = 0
3(sin2x + cos2x) = 0 /3
sqrt(2) *sin(2x+pi/4) = 0 /sqrt(2)
2х+pi/4 = pi*n, n є Z;
2x = -pi/4 + pi*n, n є Z;
x = -pi/8 + (pi*n)/2, n є Z;