# Limit of an exponent when it goes to infinity

how this thing works ?

integration of e to the power of (-x) from 0 to infinity

sorry , not good in using the symbols ..^.^ ~

Hi
Do you know what the primitive of e^{-x} is ?

First integrate it, then you get [-e-x] from 0 to infinity.

The key is to find the limit as x approaches infinity of (-e-x).

(Hint: Put in a very large negative value for x and see what you get.)

sorry ..~ i missed out the negative ..~
now i know already ..~ tq tq ...