Trigonometric Identities

• August 8th 2010, 12:06 PM
MATNTRNG
Trigonometric Identities
What is equivalent to the value of sin(A+B) if sinA = cosB?

I know the answer is 1. I just can't see how to get their using the trig identities.
• August 8th 2010, 12:14 PM
Quote:

Originally Posted by MATNTRNG
What is equivalent to the value of sin(A+B) if sinA = cosB?

I know the answer is 1. I just can't see how to get their using the trig identities.

If sinA=cosB, then cosA=sinB also. Why?

$cos^2B+sin^2B$
$sin^2A+cos^2A$