Final answer:
To find the joint probability function of f(x,u) given that u = y/x, we can use the conditional probability formula.
Step-by-step explanation:
To find the joint probability function of f(x,u) given that u = y/x, we need to consider the conditional probability.
The joint probability function is defined as P(X = x, U = u).
We can rewrite this as P(x, y/x).
Next, we can use the conditional probability formula:
P(x, y/x) = P(x) * P(y/x) = P(x) * P(y|x)