3sin^2х-4sinxcosx+5cos^2x-2=0
3sin^2х-4sinxcosx+5cos^2x-2•(sin^2x+cos^2x)=0
3sin^2х-4sinxcosx+5cos^2x-2sin^2x-2cos^2x=0
Sin^2x-4sinxcosx+3cos^x=0. (:cos^2x)
tg^2x-4tgx+3=0
tgx=t
t^2-4t+3=0
D=16-12=4
t1=(4+2):2=3
t2=(4-2):2=1
tgx=1
X=arctg1+Пк;к€Z
X=П/4+Пк;к€Z
tgx=3
X=arctg3+Пк;к€Z