ABSTRACT
Exercise 757: Suppose that x1, x2, . . . are all real numbers in the interval [a, b]. Let S(n) be the statement that
a ≤ x1 + x2 + · · · + xn n
≤ b.
Base step: For n = 1, S(1) merely says that a ≤ x11 ≤ b, which is true by the assumption made on all the xi’s.
