## anonymous one year ago Use integration by parts to find the integral.

This is actually very simple if you follow the equation for by parts integration :) Let $u=t^n, du=nt^{n-1}$ and $dv=e^{-t}, v=-e^{-t}$ Then following the equation$uv-\int\limits vdu$ We get$-t^{n}e^{-t}+\int\limits nt^{n-1}e^{-t} dt$ Factor out the n from the integral in the second term and you get your final answer :)