This question already has an answer here:
This is expression for $\tan(a+b+y)$
I want to represent this with only $\tan(a)$, $\tan(b)$ and $\tan(y)$.
Clearly,I want to replace $1$ with tan functions of these three variables.
I need this answer because thie is from GelfAndSaul Trigonometry Book questions.Pg-145