examples/chebyshev-example.ss
```(require (planet "chebyshev.ss" ("williams" "science.plt")))
(require (lib "plot.ss" "plot"))

(define (f x)
(if (< x 0.5) .25 .75))

(define (chebyshev-example n)
(let ((cs (make-chebyshev-series-order 40))
(y-values '())
(y-cs-10-values '())
(y-cs-40-values '()))
(chebyshev-series-init cs f 0.0 1.0)
(do ((i 0 (+ i 1)))
((= i n) (void))
(let* ((x (exact->inexact (/ i n)))
(y (f x))
(y-cs-10 (chebyshev-eval-n cs 10 x))
(y-cs-40 (chebyshev-eval cs x)))
;(printf "~a ~a ~a ~a\n"
;        x y y-cs-10 y-cs-40)
(set! y-values (cons (vector x y) y-values))
(set! y-cs-10-values
(cons (vector x y-cs-10) y-cs-10-values))
(set! y-cs-40-values
(cons (vector x y-cs-40) y-cs-40-values))))
(printf "~a~n" (plot (mix (points (reverse y-values))
(points (reverse y-cs-10-values)))
(x-min 0) (x-max 1)
(y-min 0) (y-max 1)
(title "Chebyshev Series Order 10")))
(printf "~a~n" (plot (mix (points (reverse y-values))
(points (reverse y-cs-40-values)))
(x-min 0) (x-max 1)
(y-min 0) (y-max 1)
(title "Chebyshev Series Order 40")))))

(chebyshev-example 100)```