The uploaded image contains a set of trigonometric identity proofs. I can assist you in solving any or all of them. Let’s start with one problem at a time for clarity. Please specify which part (e.g., a, b, c, etc.) you'd like help with, or if you’d like a detailed walkthrough of the entire set.

Would you like to proceed with any specific one?
Here are 5 questions to consider based on this material:

1. What strategies are best for proving trigonometric identities?
2. How are Pythagorean identities used in solving trigonometric problems?
3. Can reciprocal trigonometric functions simplify solving identities?
4. What role do co-function identities play in problems like f?
5. Why are angle-sum and angle-difference formulas useful?

Tip: Start simplifying identities by rewriting everything in terms of sine and cosine for easier manipulation.