MU that's zero and you have e to the power power zero which will give you one and then if you are the further you go away actually could be even let's see yeah each of our zero would give you one if you go further away from you you start moving away from you this thing will become and the exponent will become a more and more negative number and that will make the expo that negative number will be a lower number and density drops it's exponential Exponential's drop very quickly that so why this nicely integrates to one