Let X and Y be independent random variables with densities fX(x) = c1x1ex, fY (y) = c2y1ey for x > 0,y > 0,> 0, >

Let X and Y be independent random variables with densities fX(x) = c1xα−1e−x, fY (y) = c2yβ−1e−y for x > 0,y > 0,α> 0,β > 0, and normalizing constants c1, c2. Find the density of W = X/(X + Y ).