Exercise 3. Suppose that f is a continuous positive decreasing function for x 2 1. For each integer i > 1 set a; := f(i). By drawing a picture, rank the following three quantities in increasing order: 5 6 -2 What significance does this have in relation to the integral comparison test for series? (Hint: Replace 6 by n (and 5 by n - 1) and consider for each of the three quantities what happens in the limit as n -+ co.)