We shall now change variables from Y and W to X and W, where X is difined by Eq.(8.7.1). The joint p.d.f. h(x,w) of X and W is obtained by first replacing y in Eq. (8.7.3) with its expression in terms of x and w and then multiplying the result by........ It follows from Eq.(8.7.1)that y = (m/n)xw and......= (m/n)w. Hence, the joint p.d.f. h(x,w) has the following form, for x > 0 and w > 0: