h(z) = 1/5z at z = 1, z = 2, and z = 4, as in Exercise 5. Find the slope between z = 1 and z = 2, and the slope between z = 2 and z = 4.
Check that the above curves do not have constant slope by computing the slopes between the points indicated. Compare with the graphs in Exercises 5 and 6 in Section 1.2.