Answer:
3
Step-by-step explanation:
Answer:
The Pythagorean identity states that

Using that we can rewrite the left denominator as:

Which can be factored as

The numerator we can expand as:

On the right hand side, let's multply numerator and denominator with (1 - sin t):
The total formula then becomes:

There you go... left and right are equal.
I am guessing it is b! because BG and BA are sides, and BAU and BGN are angles.