<h3>
Hi! It will be a pleasure to help you to prove these identities, so let's get started:</h3>
<h2>
PART a)</h2>
We have the following expression:
We know that:
Therefore, by substituting in the original expression:
We know that the basic relationship between the sine and the cosine determined by the Pythagorean identity, so:
By subtracting from both sides, we get:
<h2>
PART b)</h2>
We have the following expression:
Here, let's multiply each side by :
We also know that:
Then:
<h2>PART c)</h2>
We have the following expression:
From Angle Sum Property, we know that:
Substituting this in our original expression, we have:
But we can also write this as follows:
<h2>PART d)</h2>
We have the following expression:
By Logarithm product rule, we know:
So:
The Difference of Squares states that:
Then:
By the Pythagorean identity:
Then:
By Logarithm power rule, we know:
Then:
In conclusion: