;; numerical differentiation example for CS 313

; square function
(define f (lambda (x) (* x x)))

; cube function
(define g (lambda (x) (* x x x)))

(define (numderiv f dx)
  (lambda (x)
    (/ (- (f (+ x dx))
	  (f x))
       dx)))

(define df (numderiv f .00001))
(define dg (numderiv g .00001))

(f 5)
(df 5)
(g 2)
(dg 2)