sin2x=2sinxcosx2sinxcosx+sqrt2*sinx=0sqrt2*sinx(sqrt2*cosx+1)=0sqrt2 *sinx=0 sqrt2*cosx+1=0sin x=0 sqrt2*cosx=-1x=пn cosx=-sqrt2/2
1)Cos2x + Sin^2x=0
sin²15-cos²15=sin²15-(1-sin²15)=2sin²15-1=2=1-cos30-1=-cos30=