Sin2x+4cos^2x=0 решить уравнение

Sin2x + 4cos^2x = 0

2sinxcosx + 4cos^2x = 0

cosx (2sinx + 4cosx) = 0

1) cosx = 0

x1 = π/2 + πn, n∈Z

2) 2sinx + 4cosx = 0 / (2cosx ≠ 0)

tgx + 2 = 0

tgx = - 2

x2 = arctg ( - 2) + πk, k∈Z

x2 = - arctg (2) + πk, k∈Z