Answer:
See the proof below.
Step-by-step explanation:
For this case we need to proof the following indentity:
So we need to begin with the definition of tangent, we know that and we can do this:
(1)
We also have the following identities:
Now we can apply those identities into equation (1) like this:
(2)
We can divide numerator and denominator from expression (2) by we got this:
And simplifying we got:
And that complete the proof.