Question

What is the integral of `xe^x` from -infinity to 0?

Answer 1

I found: `int_(-oo)^0xe^xdx=-1`

Explanation:

I would solve it by parts:
`intxe^xdx=xe^x-int1*e^xdx=xe^x-e^x=`
using your extrema:
`=e^x(x-1)|_-oo^0` `=`
`=-1-0=-1`

[where I used the fact that: `e^0=1 and e^-oo=1/e^oo=0`]