MCS-177, Intro. to Computer Science I, Fall 2008
Homework Assignment 2
Due: Monday, September 15

Do exercise 2.8 on page 38.
Do exercise 2.11 on page 39.
Do exercise 2.17 on page 44.
Do exercise 2.21 on page 44-45.
Below is a procedure that computes the hexagonal numbers. Use induction to prove that a call to (hexagonal n) terminates with the value 2n^2- n.

(define hexagonal
    (lambda (n)
(if (= n 1)
         1
           (+ (hexagonal (- n 1))
          (- (* 4 n) 3)))))