sinx-✓(1-3sin2x)=0
-✓(1-3sin2x)=-sinx
apply squared both sides
(-✓(1-3sin2x)^2=(-sinx)^2
1-3sin2x=sin2x
collect like terms
-3sin2x-sin2x+1=0
-4sin2x+1=0
-4sin2x=-1
devide both sides by -4
sin2x=-1/-4
sin2x=0.25
sinx*sinx =0.25
[sinx]^2 = 0.25
apply square root both sides
✓(sinx)2 = ✓0.25
sinx=0.5
x=sin^-(0.5)
x=30°
check quadrant where sin is positive, sin is +ve in second quandrant
180-x= Theta(X)
180-30=X
X=150°
therefore, all angles for sinx -✓(1-3sin2x)=0 are (X= 30° and 150°)