1)cos(3x-2)=√2/2
3x-2=±п/4+2пк,к€z
3x=2±п/4+2пk,k€z
x=2/3±п/12+2пk/3,k€z
2)3sin²2x+7cos2x-3=0
3(1-cos²2x)+7cos2x-3=0
3-3cos²2x+7cos2x-3=0
-3cos²2x+7cos2x=0
cos2x(-3cos2x+7)=0
cos2x=0
2x=п/2+пn,n€z
x=п/4+пn/2,n€z
-3cos2x=-7
cos2x=7/3
∅ x€[-1;1]
3)3cos²x-5sin²x-sin2x=0
3cos²x-5sin²x-2sinxcosx=0 |:cos²x
3-5tg²x-2tgx=0
-5tg²x-2tgx+3=0
tgx=t
-5t²-2t+3=0
D=4-4*(-5)*3=4+60=64
t1=2+8/-10=-1
t2=2-8/-10=-6/-10=0,6
tgx=-1
x=-п/4+пn,n€z
tgx=0,6
x=arctg0,6+пk,k€z