2tg²x+3=3/cosx
2sin²x/cos²x+3=3/cosx
(2sin²x+3cos²x)/cos²x=3/cosx
(2sin²x+3cos²x)/cos²x=3/cosx
(2sin²x+3cos²x)/cosx=3
2sin²x+3cos²x=3cosx
cos²x+2=3cosx
cos²x-3cosx+2=0
y²-3y+2=0, y=cosx
y1=2, y2=1
cosx=2 --> ∅
cosx=1 --> x=2πn, n∈Z
ответ: x=2πn, n∈Z
