1)10sin^2x+11sinx-8=0 решите

1)
10sin(x)+11sin(x)-8=0
sin(x)=t, t1
10t+11t-8=0
D=121+320=441=21
t1=(-11+21)/20=1/2
t2=-(11-21)/20=-1.6t1

sin(x)=1/2
x=(-1)^n *arcsin(1/2)+n,nZ
x=(-1)^n */6 +n, nZ




2)
4sin(x)-11cos(x)-11=0
4(1-cos(x))-11cos(x)-11=0
4-4cos(x)-11cos(x)-11=0
4cos(x)+11cos(x)+7=0
cosx=t, t1
4t+11t+7=0
D=121-112=9=3
t1=(-11+3)/8=-1
t2=(-11-3)/8=-7/4t1

cos(x)=-1
x=+2n,nZ



3)
4sin(x)+9sin(x)cos(x)+2cos(x)=0     :(cos(x)