Trigonometric Identities

We are given that:

Step 1: Square both sides.
Squaring both sides of the equation: Expanding the left-hand side:
Step 2: Use the Pythagorean identity.
Using the Pythagorean identity , we get:
Step 3: Solve for .
Simplifying the equation: Thus, we have:
Step 4: Use the identity for .
Now, we know that: Using the identity for , we can find as:
Step 5: Solve for .
We now have enough information to calculate using the
given values and standard trigonometric formulas. Using these, we find:
Thus, the correct answer is .