We are given the following trigonometric expression:

We are asked to put this expression as a function of sines and cosines, t do this, let's remember the following relationship:

Now we replace this in the expression:

Now we do the operation in the numerator, like this:

We simplify the result:

now we use the following relationship:

replacing this in the expression

simplifying:

Since we are asked to put the expression as a function of sines and cosines we can't simplify any further, therefore the previous expression is the result.