Question

How do you verify `(sin(x)cos(y)+cos(x)sin(y))/(cos(x)cos(y)-sin(x)sin(y)) = (tan(x)+tan(y))/(1-tan(x)tan(y))`?

Answer 1

Use the sum and difference identities.

Explanation:

Using the poster above:

`(sin(x + y))/(cos(x + y)) = tan(x + y)`

Applying the quotient identity `tantheta = sin theta/costheta`:

`tan(x + y) = tan(x + y)`

Identity proved!!!! :)

Hopefully this helps!