Prove that:
Prove that:2 cosA sinB = sin (A + B) - sin (A - B)
Prove that:2 cosA cosB = cos (A + B) + cos (A - B)
Prove that:-2 sinA sinB = cos (A + B) - cos (A - B)
Prove the following:
Let and R.H.S. = = cos (x + y) + cos (x - y) = Hence,