SICP https://sarabander.github.io/sicp/html/index.xhtml

exercise-1.3.rkt

#lang sicp
;#lang racket

(define (square x) (* x x))

(define (sum-of-squares x y)
  (+ (square x) (square y)))

(define (sum-two-largest a b c)
  (cond
    [(or (>= a b c) (>= b a c)) (sum-of-squares a b)]
    [(or (>= a c b) (>= c a b)) (sum-of-squares a c)]
    [else (sum-of-squares c b)]
    ))

;(require racket/trace)
;(trace sum-two-largest)

(sum-two-largest 1 1 1)
(sum-two-largest 3 2 1)
(sum-two-largest 2 3 1)
(sum-two-largest 2 1 3)
(sum-two-largest 3 1 3)
(sum-two-largest 3 3 1)
(sum-two-largest 1 3 3)
(sum-two-largest 3 3 3)

exercise-1.6.rkt

#lang racket
;#lang sicp

(define (square x) (* x x))

(define (improve guess x)
  (average guess (/ x guess)))

(define (average x y) 
  (/ (+ x y) 2))

(define (sqrt x)
  (sqrt-iter 1.0 x))

(define (sqrt-iter guess x)
  (new-if (good-enough? guess x)
          guess
          (sqrt-iter (improve guess x) x)))

(define (new-if predicate 
                then-clause 
                else-clause)
  (cond (predicate then-clause)
        (else else-clause)))

(define (good-enough? guess x)
  (< (abs (- (square guess) x)) 0.001))

;(define (sqrt-iter guess x)
;  (if (good-enough? guess x)
;      guess
;      (sqrt-iter (improve guess x) x)))

(require racket/trace)
(trace sqrt-iter)
(trace good-enough?)
(trace new-if)
(trace square)
(trace improve)
(trace average)


(sqrt 9)