-
Notifications
You must be signed in to change notification settings - Fork 0
/
2_10.scm
39 lines (31 loc) · 1.34 KB
/
2_10.scm
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
(define (add-interval x y)
(make-interval (+ (lower-bound x) (lower-bound y))
(+ (upper-bound x) (upper-bound y))))
(define (sub-interval x y)
(make-interval (- (lower-bound x) (upper-bound y))
(- (upper-bound x) (lower-bound y))))
(define (mul-interval x y)
(let ((p1 (* (lower-bound x) (lower-bound y)))
(p2 (* (lower-bound x) (upper-bound y)))
(p3 (* (upper-bound x) (lower-bound y)))
(p4 (* (upper-bound x) (upper-bound y))))
(make-interval (min p1 p2 p3 p4)
(max p1 p2 p3 p4))))
(define (div-interval x y)
(if (or (= 0 (upper-bound y)) (= 0 (lower-bound y)))
(error "could not divide by inteval which spans 0" y)
(mul-interval x
(make-interval (/ 1.0 (upper-bound y))
(/ 1.0 (lower-bound y))))))
(define (display-interval interval)
(newline)
(display (lower-bound interval))
(display "...")
(display (upper-bound interval)))
(define (make-interval a b) (cons a b))
(define (lower-bound interval) (car interval))
(define (upper-bound interval) (cdr interval))
(display-interval (add-interval (make-interval 3 4) (make-interval 5 6)))
(display-interval (mul-interval (make-interval 3 4) (make-interval 5 6)))
(display-interval (sub-interval (make-interval 3 4) (make-interval 5 6)))
(display-interval (div-interval (make-interval 3 4) (make-interval 0 6)))