Part can’t get what ya want sooo idk what to tell u sorry not sorry
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.