Question

( sin theta+sin 2 theta+sin 3 theta=sin alpha )
( frac{2 sin 2 theta cos theta+sin 2 theta=sin alpha}{alpha operatorname{cin} 2 theta(2 cos theta+1)=sin alpha} mid frac{cos theta+cos 2 theta+cos 3 theta=cos alpha}{2 cos 2 theta cos theta+cos 2 theta=cos alpha} )
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¿iniding 12 ( tan 2 theta=tan alpha )
( 2 theta=infty cdot 2 )
( T theta=frac{alpha}{2} )

# 22. If sine + sin 20 + sin30 = sina and cose + cos20 + cos30 = cosa, then is equal to o la (3) 20

Solution