You can 
put this solution on YOUR website! 
This is NOT an identity because the right side has 
the same numerator and denominator and therefore
the right side equals to 1.
Therefore 
sinA tanA = 1
This has solutions approximately 51.8° and 308.2°.
So it is not an identity.
The problem is botched.  You may post the correct
identity in the thank-you note and I'll help you.
Edwin