Prove the identity: csc²x - cot²x = 1. a. Use the Pythagorean identities and simplify csc²x - cot²x b. Use the reciprocal identities to rewrite csc²x and cot²x c. Substitute sin(x) and cos(x) into csc²x and cot²x and simplify d. Use the unit circle to prove that csc²x - cot²x = 1