Prove the identity. 1 + sin x COS X COS X 1 - sin x To verify the identity, start with the left side and transform it to obtain the right side. Choose the correct step and transform the expression according to the step chosen. 1 + sin x 1 + sin x Apply a reciprocal identity. COS X COS X Apply a reciprocal identity. Add and subtract by a form of 1. Multiply by a form of 1