Write a program to simulate the random variables whose densities are given by the following, making a suitable bar graph of each and comparing the exact density with the bar graph.
(a) fX (x) = e-x on [0, ∞) (but just do it on [0, 10]). (b) fX (x) = 2x on [0, 1].
(c) fX (x) = 3x2 on [0, 1].
(d) fX (x) = 4|x - 1/2| on [0, 1].