2sin²x+sinx-1=0 D=1+8=9 √D=3
sinx1=1/4[-1+3]=1/2 x1=(-1)ⁿπ/6+πn n∈Z
sinx2=1/4[-1-3]=-1 x2=3π/2+2πn n∈Z
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3cos²x-sinx+1=0
3(1-sin²x)-sinx+1=0
-3sin²x-sinx+4=0
3sin²x+sinx-4=0 D=1+48=49 √D=7
sinx1=1 sinx2=-8/6<-1<br>
sinx=1 x=π/2+2πn n∈Z