# Math Help - identity question

1. ## identity question

i am also having trouble with this identity!

tan ( pi /4 + x ) - tan ( pi /4 - x ) = 2 sinx cosx
tan ( pi /4 + x ) + tan ( pi /4 - x )

EDITTED!

2. It is wrong because
$\tan (\pi + x) = \tan x$ and $\tan (\pi - x) = - \tan x$

3. sorry about that, editted!

4. The first step is to realize that,
$\tan (\pi/4 + x) = \frac{\tan \pi/4 + \tan x}{1 - \tan \pi/4 \cdot \tan x} = \frac{1+\tan x}{1-\tan x}$
Similarly,
$\tan (\pi/4 - x) = \frac{1-\tan x}{1+\tan x}$.

Now, simplify the fraction and see what you get.

5. That's what I did, but the answer is not coming up.

Do I have to do something to the left side?