按定义计算出黄金分割率的值：
;;; 35-golden-ratio.scm
(load "p46-fixed-point.scm")
(define golden-ratio
(fixed-point (lambda (x)
(+ 1 (/ 1 x)))
1.0))
测试：
1 ]=> (load "35-golden-ratio.scm")
;Loading "35-golden-ratio.scm"...
; Loading "p46-fixed-point.scm"... done
;... done
;Value: golden-ratio
1 ]=> golden-ratio
;Value: 1.6180327868852458