# Thread: verify that f(x) is a pdf

1. ## verify that f(x) is a probability density function

f(x)= 32/(x+4)^3 for x>0

how do i verify f(x) is a pdf, i know f(x) has to be integrated, but between which limits cos i can't seem to get 1

2. ## Re: verify that f(x) is a pdf

Hi oyinkan,

Integrating over $\displaystyle (0, \infty)$ should do the trick.

Good luck!

3. ## Re: verify that f(x) is a pdf

The problem says "x> 0" so your integration should be from 0 to infinity.