I have a test tomorrow over L'Hopital's Rule and Improper Integrals. I understand how they work, but I'm having trouble figuring out when an integral (or it's limit I should say) is going toward infinity or towards 0. For example, how do I know what the limit as x approaches infinity of e^x is? And the whole infinity/zero or zero/infinity what those approach... I just don't understand the way the zero or infinity thing works with limits. Any sort of explanation/example would be helpful to me at this point.

Thanks in advance!