I can't get these 3 questions, can someone help me?(adsbygoogle = window.adsbygoogle || []).push({});

1. cotB [ (tanA + TanB) / (cotA+cotB) ] = tan A

2. (sin^2A + 2cosA - 1) / (2 + cosA - cos^2A) = 1 / (1+ secA)

3. cos^3A + sin^3A = (cosA+SinA)(1-SinAcosA)

please help out on these, thx in advance. U can write the / sign as fractions cuz i can't do it on the computer here.

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Trig Identities : Help 3 Questions.

**Physics Forums | Science Articles, Homework Help, Discussion**