## pottersheep Group Title Grade 12 Trig Identities trouble....help please... I'm not sure how to prove that ((sin2x/(1+cos2x)) * (cosx)/(1+cosx) = tan(x/2) one year ago one year ago

1. sirm3d Group Title

try the double angle formulas $\large \sin 2x=2\sin x \cos x$and$\large \cos 2x = 2\cos^2 x -1$

2. pottersheep Group Title

Yep that's what I have tried out...I keep getting stuck though

3. pottersheep Group Title

because one side is tan(x/2)

4. chaguanas Group Title

I've tried it and find what I think is the answer. See if you can find it; I used this page http://www.sosmath.com/trig/douangl/douangl.html

5. pottersheep Group Title

Thank you very much I will go take a look