Question

if A,Band C are interior angles if a triangle ABC then show that tan (A+B/2)=cot c/2

Answer 1

$\alpha + \beta + \gamma = \pi \\ \tan( \frac{ \alpha + \beta }{2} ) = \tan( \frac{\pi - \gamma }{2} ) = \tan( \frac{\pi}{2} - \frac{ \gamma }{2} ) = \cot( \frac{ \gamma }{2} )$