Помогите решить cos2x-2sin2x=2

2cos²x - 1 - 2 - 4sinxcosx = 0

2cos²x - 4sinxcosx - 3 = 0

-cos²x - 4sinxcosx - 3sin²x = 0

3sin²x + 4sinxcosx + cos²x = 0|:cos²x

3tg²x + 4tgx + 1 = 0

tg²x + 4/3 tgx + 1/3 = 0

tgx = - 1 tgx = - 1/3

x = - П/4 + Пn x = - arctg1/3 + Пn