SOLUTION: Rewrite the expression as a triginometric function of a single measure <pre> tan(4&#952;) + tan(2&#952;) ----------- ------- 1 - tan(4&#952;)tan(2&#952;)</pre>

  tan(4θ) + tan(2θ)
-------------------
 1 - tan(4θ)tan(2θ)

Recall the identity 

Observe that your expression is the same as the right side
of that identity, where a = 4q and b = 2q  

Therefore, if you substitute those into that identity, you get

 

The right side is exactly your expression, so the answer is the
left side 

tan(4q + 2q)

which is 

tan(6q)

Edwin