Let's verify the identity

In this next part, we'll use a trick: add and subtract

** A. ** ** B. ** ** C. ** ** D. ** ** E. ** ** F. ** None of the above

What do we get when we simplify the right-hand side?

** A. ** ** B. ** ** C. ** ** D. ** ** E. ** ** F. ** None of the above

What do you get when you multiply the fraction in the right-hand side by

** A. ** ** B. ** ** C. ** ** D. ** ** E. ** ** F. ** None of the above

Let's simplify the previous expression and figure out what equation we are working with now. What do we have?

** A. ** ** B. ** ** C. ** ** D. ** ** E. ** ** F. ** ** G. ** None of the above

How can we finish the proof?

** A. ** We may add ** B. ** After rearranging terms, both sides are identical.** C. ** After rearranging terms and simplifying, we are left with the definition of secant.** D. ** After rearranging terms and simplifying, we are left with the double angle formula for sine.** E. ** None of the above