Solution to Exercise 1.37:

`; part a (recursive process)`

(define (cont-frac n d k)

(define (sub-expr i)

(if (= i k)

(/ (n i) (d i))

(/ (n i) (+ (d i) (sub-expr (+ i 1))))))

(sub-expr 1))

```
```(define (golden-ratio k)

(cont-frac (lambda (i) 1.0)

(lambda (i) 1.0)

k))

(define (iterations-required)

(define (iter i previous)

(let ((current (golden-ratio i)))

(if (= (round (* current 10000))

(round (* previous 10000)))

(- i 1)

(iter (+ i 1) current))))

(iter 1 0.0))

; > (iterations-required)

; 12

`; part b (iterative process)`

(define (cont-frac-i n d k)

(define (iter i sub-expr)

(if (= i 0)

sub-expr

(iter (- i 1) (/ (n i) (+ (d i) sub-expr)))))

(iter (- k 1) (/ (n k) (d k))))