cost Verify the identity: tant + sect 1 + sint To verify the identity, start with the more complicated side and transform it to look like the other side. Express in terms of sines and cosines. cost sin ( t) cost tant + 1 + sint cost 1 + sint Combine the fractions together. Do not apply any identities in this step. Apply a Pythagorean identity to the numerator. Do not cancel any terms in this step. Divide out the common factor and apply a reciprocal identity