Решите уравнения:
1)2cos(2x-п/3)-1=0
2)7sin^2x-9sinx*cosx=-1
3)sin2x+cos(6x-п/3)=0

Большое спасибо

1)2cos(2x-п/3)-1=0cos(2x-π/3)=1/22x-π/3=-π/3+2πk U 2x-π/3=π/3+2πk2x=2πk U 2x=2π/3+2πkx=πk U x=π/3+2πk,k∈z2)7sin^2x-9sinx*cosx=-17sin²x-9sinxcosx+sin²x+cos²x=08sin²x-9sinxcosx+cos²x=0/cos²x8tg²x-9tgx+1=0tgx=t8t²-9t+1=0D=81-32=49t1=(9-7)/16=1/8⇒tgx=1/8⇒x=arctg1/8+⇒k,k∈zt2=(9+7)/16=1⇒tgx=1⇒x=π/4+πk,k∈z3)sin2x+cos(6x-п/3)=0cos(π/2-2x)+cos(6x-π/3)=02cos(2x+π/12)*cos(4x-5π/12)=0cos(2x+π/12)=0⇒2x+π/12=π/2+πk⇒2x=5π/12+πk⇒x=5π/24+πk/2,k∈zcos(4x+5π/12)=0⇒4x+5π/12=π/2+πk⇒4x=π/24+πk⇒x=π/96+πk/4.k∈z