Limit of a proper integral.

[KoryME]

I can't find any help or examples of how to solve this example problem in my book, so I'm not even sure where to begin.

Find the limit of the proper integral [(x-1)e^(-x) dx] from 0 to infinity. Thanks in advance!

 

[mmm4444bot]

If it were from 0 to 1, instead, what would you think about the integral?

 

[Deleted member 4993]

I can't find any help or examples of how to solve this example problem in my book, so I'm not even sure where to begin.

Find the limit of the proper integral [(x-1)e^(-x) dx] from 0 to infinity. Thanks in advance!

Your question does not make sense to me.

Please re-read your post and fix it as needed.

And...

Please share your work with us, indicating exactly where you are stuck - so that we may know where to begin to help you.

 

[HallsofIvy]

Probably the simplest way to integrate \(\displaystyle \int (x- 1)e^{-x}dx\) is by parts, letting u= x- 1 and \(\displaystyle dv= e^{-x}dx\).