Add or subtract as indicated, and then simplify as much as possible. Leave your answer in terms of
sines and cosines only.

To solve the equation, we start by rewriting the term using sine and cosine. We know that , but as per your request, we want to keep it strictly in terms of sine and cosine.

Thus, the expression becomes:

However, knowing that , we can combine the terms into a single fraction. To do this we will multiply by :

Now combining the two terms results in:

Thus we have:

And this can be simplified down as needed, but it will remain in terms of sine and cosine!