4cos^2x+sinx cosx+3sin^2x-3=0

4cos²x + sinx * cosx + 3sin²x - 3 = 0 4cos²x + sinx * cosx + 3sin²x - 3(sin²x + cos²x) = 04cos²x + sinx * cosx + 3sin²x - 3sin²x - 3cos²x = 0cos²x + sinx * cosx = 0 cosx * (cosx + sinx)=0cosx = 0   x=π/2 + πn,n ∈ Zcosx + sinx = 0 |:cosx 1+ tgx = 0 tgx = -1  x=-π/4 + πn,n ∈