tan^2(1/2 theta)=(tan theta-sin theta)/(tan theta + sin theta)tan2(12θ)=tanθ−sinθtanθ+sinθ
Right Side =(tan theta-sin theta)/(tan theta + sin theta)=tanθ−sinθtanθ+sinθ
=(sin theta / cos theta -sin theta)/(sin theta/cos theta + sin theta)=sinθcosθ−sinθsinθcosθ+sinθ
=((sin theta-sin theta cos theta) / cos theta) / ((sin theta+sin theta cos theta)/cos theta)=sinθ−sinθcosθcosθsinθ+sinθcosθcosθ
=(sin theta-sin theta cos theta) / cos theta * cos theta/(sin theta+sin theta cos theta)=sinθ−sinθcosθcosθ⋅cosθsinθ+sinθcosθ
=(sin theta-sin theta cos theta)/(sin theta+sin theta cos theta)=sinθ−sinθcosθsinθ+sinθcosθ
=(sin theta(1-cos theta))/(sin theta(1+cos theta))=sinθ(1−cosθ)sinθ(1+cosθ)
=(1-cos theta)/(1+cos theta)=1−cosθ1+cosθ
=(tan (1/2 theta))^2=(tan(12θ))2
=tan^2(1/2 theta)=tan2(12θ)
== Left Side