I'm getting very confused...there are too many formula for this!

Prove:

1. sin (A+B) + cos (A-B) (sin A+ cos A)(sin B + cos B)

2. tan (A+B) - tan A

And one more extra:

3. In triangle ABC, AB=p, BC=3p, and . The bisector of the angle ABC meets AC at the point T. Find AT and CT in terms of p.

Answer: