### Mathematics - Trigonometry - Identities

Prove the following Identities: Prove the following Identities: 1. tan² A / sec² A = 1 - cot ² A / csc² a 2. 1 / 1 - cos A tan A = cot A / cot A - cos A 3. cos² A ( 1 - sec² A) / cot² A sin² A - 1 = 1 4. (cot A = tan A) ² = sec² B csc² B°