Subversion Repositories programming

;Written by: Ira Snyder
;Date:       01-13-2005
;Project #:  Hw 02
;License: Public Domain

;define a function to calculate the result of the infix expression
; -b + sqrt( -b^2 - 4*a*c )

(defun QUAD-MINUS (A B C)
  (/ 
    (+ (- B) (sqrt (- (* B B) (* 4 A C))))
    (* 2 A)
  )
)

;define a function to calculate the result if the infix expression
; -b - sqrt( -b^2 - 4*a*c )

(defun QUAD-PLUS (A B C)
  (/ 
    (- (- B) (sqrt (- (* B B) (* 4 A C))))
    (* 2 A)
  )
)

;define a function that evaluates to a list containing both
;roots provided by the quadratic function

(defun QUAD2 (A B C)
  (list (QUAD-MINUS A B C) (QUAD-PLUS A B C))
)