# Thread: Joint Distrubution

1. ## Joint Distrubution

Let Y and Z be two independent continuous random variables with common probability density function f(x):
$2e^{-2x}$ if $x \geq 0$
$0$ if $x<0$.

How do you calculate the joint probability density function? I know how to do it the other way round, but I cannot see how to do this?
Thanks

2. ## Re: Joint Distrubution

are z and y independent?

if so f(z,y) = f(z)f(y)