hi there,
I need help solving the following problem using U-substitution:
any idea what I should set my u variable equal to?
any help would be greatly appreciated
thanks so much & all the best
- xecutioner
Let $\displaystyle \displaystyle \begin{align*} u = e^x + 4 \implies du = e^x\,dx \end{align*}$ and the integral becomes
$\displaystyle \displaystyle \begin{align*} \int{\frac{e^x}{\left(e^x + 4\right)^3}\,dx} &= \int{\frac{1}{u^3}\,du} \\ &= \int{u^{-3}\,du} \end{align*}$
I'm sure you can go from here