Question

My biggest weakness; Half-Identities. Anyone wanna take a stab at it and help me? <:)

Answer 1

I know I'm going to need to use this identitiy;
tan theta/2 = +- sqrt. ((1- cos theta)/(1 + cos theta))

Answer 2

\[\tan \theta/2 = \pm \sqrt{(1-\cos \theta) / (1 + \cos \theta)}\]

Answer 3

I just don't know how to set anything up.