Any help would be appreciated, thanks!

5. (*) A random sample X = (X1,X2,X3) of size n = 3 is taken from a population with density f($) = 2:3,:1: 6 [0,1]. a) Evaluate the covariance between X (1) and X (3). b) Evaluate the correlation between X (1) and X (3). c) Find the density of the range R = X (3) X (1) and show that E(R) = 0.4 holds