Generate a random variable with an exponential distribution

Question

In Matlab using the rand routine, how should I write the code to generate 500 samples from an exponential distribution, whose pdf is:

(1/mu)*exp(-x/mu); x>=0

Answer 1

Assuming you really have to do it using the rand function: exploit the property that the minus logarithm of a normalized uniform RV is a normalized exponential RV:

samples = -mu*log(rand(1,500));