exam2.2.3

;; mht created on Nov 9, 2011

;; equation1 : number -> boolean
;; to determine whether x is a solution for x^2+2*x+1=0
(define (equation1 x)
  (= (+ (* x x) (* 2 x) 1) 0))

; test
(equation1 1)

;; equation2 : number -> boolean
;; to determine whether x is a solution for 4n+1=62
(define (equation2 x)
  (= (+ (* 4 x) 1) 62))

(equation2 14)

;; equation3 : number -> boolean
;; to determine whether x is a solution for 2*n^2=102
(define (equation3 x)
  (= (* 2 (* x x)) 102))
(equation3 14)

;; equation4 : number -> boolean
;; to determine whether x is a solution for 4*n^2+6n+2=462
(define (equation4 x)
  (= (+ (* 4 (* x x)) (* 6 x) 2) 462))
(equation4 10)