Let X and Y be independent exponential random variables with and

Find the joint probability distribution .

I know that the probability density function for X is for x>0 and 0 otherwise.

also

I know that the probability density function for Y is for x>0 and 0 otherwise.

I am not sure about jointly. Do I simply multiply them together?

Find .

I have no idea how to begin this part, although I know the answer is .04.

Can anyone help?