If is an acute angle and then is equal to
Explanation for the correct option.
Step 1. Find the value of
Let's consider the given functions
Squaring on both sides,
Step 2. Find the value of .
Multiply by and
Step 3. Find the value of :
Squaring both sides and use the identity to find the value of .
Step 4. Find the value of .
Using , the value is found as:
Hence, the correct option is B.