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