Exercise 3.5
A discriminant function in continuation passing style **

Program the following discriminant function (lambda (a b c) (- (* b b) (* 4 a c))) in continuation passing style (CPS).

 
(define (discriminant a b c)
  (sub (square b) (mult (mult 4 a) c)))

; AUX functions:
(define (square a)
  (mult a a))

(define (mult a b)
  (* a b))

(define (sub a b)
  (- a b))

In the program above we have provided auxilliary functions for squaring, multiplication and subtraction. These functions must be provided with an extra continuation parameter when you program the CPS variants of the functions. Consider different evaluation orders, and how it affects the CPS variant of the functions.