A number x is an element [0, infinity] is selected so as to have an exponential distribution with parameter alpha >0, that is fx(X) = alpha* e^-alpha*x for all x>=0 and zero otherwise. Once X = x is chosen, a second number Y is select so that it is uniformly distributed on the interval [ x, x+ beta] for soe constant B > 0.

Calculate the conditional density function of f[y|x=x](y)?

Ok so i knwo the formula for this is fx,y(x,y)/fy(y) but i have no idea where to get the y part....

The answer is given by 1/beta....