integration - Integral of $int^1_0 frac{dx}{1+e^{2x}}$

I am trying to solve this integral and I need your suggestions.
I think about taking $1+e^{2x}$ and setting it as $t$, but I don't know how to continue now.

$$\int^1_0 \frac{dx}{1+e^{2x}}$$
Thanks!

Answer

With the change of variable $u=e^{x}$, you get
$$
\int_{[0,1]}\frac{dx}{1+e^{2x}} = \int_{[1,e]}\frac{1}{u(1+u^2)}du
$$