I have this math problem I am trying to understand, I am supposed to derivate this:
$f(x) = \frac{e^x}{1+x}$
And I know the answer and how to work it:
$f'(x) = \frac{e^x (1+x) - e^x \cdot 1}{(1 + x)^2}$
The problem I have is that I can't explain what happens next ->
http://yeyfiles.net/547701918/math.png
If I should do it, I'd think $e^x - e^x = 0$
can someone explain to me in an easy way what's happening? :)
Thanks.