# Math Help - Help with improper integrals

1. ## Help with improper integrals

the integral from neg. infinity to 6 of re^(r/3)

thanks!

2. $\int_{-\infty}^6re^{\frac{r}{3}}dr=\lim_{a\to-\infty}\int_a^6rd^{\frac{r}{3}}=$

$\lim_{a\to-\infty}3re^{\frac{r}{3}}-9e^{\frac{r}{3}}|_{a}^{6}$

I used integration by parts