; 9.1.scm
; 2024-10-12
; $Id: 9.1.scm 1.1 2024/11/02 14:09:11 s Exp $

(define (main args)
    ; procedure
    (define sum (lambda (x) (fold + 0 x)))
    (define u   (lambda (x) (expt x (/ 4))))

    ; input 
    (define x (list 80e3 90e3 100e3 110e3 120e3 130e3 140e3))

    ; calculation
    (define eu_x (/ (sum (map u x)) (length x)))
    (define c    (expt eu_x 4))

    ; output
    (print "9.1.scm");
    (print "x " x)
    (format #t "~10a ~f\n" "E[U(x)] " eu_x)
    (format #t "~10a ~f\n"   "C "        c)
0)
; end