;;; 3.7.scm
;;; 2016-02-13
(define (main args)
  ; input
  (define r 0.1)
  (define cfsa '(-20000 -1000 -1000 -1000 0))
  (define cfsb '(-30000 -2000 -2000 -2000 -2000 -2000 0))
  (define ia '(0 1 2 3))
  (define ib '(0 1 2 3 4 5))
  ; calculate
  (define pva (fold + 0 (map (lambda (x y) (/ x (expt (+ 1 r) y))) cfsa ia)))
  (define pvb (fold + 0 (map (lambda (x y) (/ x (expt (+ 1 r) y))) cfsb ib)))
  (define na (length ia))
  (define nb (length ib))
  (define aa (/ (* r (expt (+ 1 r) na) (- pva)) (- (expt (+ 1 r) na) 1)))
  (define ab (/ (* r (expt (+ 1 r) nb) (- pvb)) (- (expt (+ 1 r) nb) 1)))
  ; output
  (print "input")
  (print "r= " r)
  (print "cfsa= " cfsa)
  (print "ia= " ia)
  (print "na= " na)
  (print "output")
  (print "pva= " (round pva))
  (print "aa=  " (round aa))
  (print "input")
  (print "cfsb= " cfsb)
  (print "ib= " ib)
  (print "nb= " nb)
  (print "output")
  (print "pvb= " (round pvb))
  (print "ab= " (round ab))
0)
;;; end