Start on the left side.
Convert to sines and cosines.
Write in sines and cosines using the quotient identity.
Apply the reciprocal identity to .
Multiply the numerator by the reciprocal of the denominator.
Cancel the common factor of .
Write as a fraction with denominator .
Factor out the greatest common factor .
Cancel the common factor.
Rewrite the expression.
Because the two sides have been shown to be equivalent, the equation is an identity.
is an identity