2. Suppose that the random variables Y1 and )2 have joint probability density function, f(y1, )2), given by f(y1. y2) = 671 12, 0 5 VI S y2, y1 + 12 5 2 0, elsewhere (a) (4 pts) Derive the marginal density of Y1. (b) (4 pts) Derive the marginal density of Y2. (Hint: this will have to broken down into two parts!!!) (c) (4 pts) Derive the conditional density of Yz given Y1 = y1