1 ;; The first three lines of this file were inserted by DrScheme. They record metadata
2 ;; about the language level of this file in a form that our tools can easily process.
3 #reader(lib "htdp-intermediate-reader.ss" "lang")((modname 21.1.2) (read-case-sensitive #t) (teachpacks ((lib "draw.ss" "teachpack" "htdp"))) (htdp-settings #(#t constructor repeating-decimal #f #t none #f ((lib "draw.ss" "teachpack" "htdp")))))
4 #|
5 
6 Exercise 21.1.1.   Define tabulate, which is the abstraction of the following two functions:
7 
8 ;; tabulate-sin : number  ->  lon
9 ;; to tabulate sin between n 
10 ;; and 0 (inclusive) in a list
11 (define (tabulate-sin n)
12   (cond
13     [(= n 0) (list (sin 0))]
14     [else
15       (cons (sin n)
16 	(tabulate-sin (sub1 n)))]))
17      	
18 ;; tabulate-sqrt : number  ->  lon
19 ;; to tabulate sqrt between n 
20 ;; and 0 (inclusive) in a list
21 (define (tabulate-sqrt n)
22   (cond
23     [(= n 0) (list (sqrt 0))]
24     [else
25       (cons (sqrt n)
26 	(tabulate-sqrt (sub1 n)))]))
27 
28 Be sure to define the two functions in terms of tabulate. Also use tabulate to define a tabulation function for sqr and tan. What would be a good, general contract?    Solution
29 
30 |#
31 
32 ;tabulate : (number -> X) number -> (listof X)
33 ;Given op and n, return the value of (op i) where i is an integer, for integers from n to 0, inclusive.
34 
35 (define (tabulate op n)
36   (cond
37     [(= n 0) (list (op 0))]
38     [else (cons (op n)
39                 (tabulate op (sub1 n)))]))
40 
41 ;tabulate-sin : number -> (listof number)
42 ;Tabulate the sin of all integers from n to 0 inclusive.
43 (define (tabulate-sin n)
44   (tabulate sin n))
45 
46 ;tabulate-sqrt : number -> (listof number)
47 ;Tabulate the sqrt of all integers from n to 0 inclusive.
48 (define (tabulate-sqrt n)
49   (tabulate sqrt n))