Integral of (e^x)/(e^(2x)+3) dx
U-substitution and integration by parts doesn't seem to be working for me...
Krizalid is not suggesting a trig substitution ....
Actually, I think the substitution he intended was $\displaystyle e^x = \sqrt{3} u \Rightarrow e^{2x} = 3 u^2$ and $\displaystyle \frac{du}{dx} = \frac{e^x}{\sqrt{3}} \Rightarrow dx = \frac{\sqrt{3}}{e^x} = \frac{\sqrt{3}}{u}$.
So hop to it, make the substitution ....