Тригонометрические уравнения,срочно!

1 sinx=a 2a²-a-1=0 D=1+8=9 a1=(1-3)/4=-1/2⇒sinx=-1/2⇒x=(-1)^(n+1)*π/6+πn,n∈z a2=(1+3)/4=1⇒sinx=1⇒x=π/2+2πn,n∈z 2 4sinxcosx-3sin²x-sin²x-cos²x=0 4sin²x-4sinxcosx+cos²x=0/cos²x 4tg²x-4tgx+1=0 (2tgx-1)²=0 2tgx=1 tgx=1/2 x=arctg1/2+πn,n∈z 3 sin(5π/6+x/2)=-√3/2 5π/6+x/2=-π/3+2πn U 5π/6+x/2=4π/3+2πn x/2=-7π/6+2πn U x/2=π/2+2πn x=-7π/3+4πn U x=π+4πn,n∈z