# Thread: identity

1. ## identity

Verify the identity sin (A - B) / sin (A + B) = (a^2 - b^2)/c^2.

2. Originally Posted by pacman
Verify the identity sin (A - B) / sin (A + B) = (a^2 - b^2)/c^2.
Does this identity refer to a triangle with sides of length a, b and c and angles A, B and C opposite those sides?

3. Yes, it refers to a triangle. . . . i use cosine law but can not arrived to the identity. . . .