1.41

Exercise 1.41: Define a procedure double that takes a procedure of one argument as argument and returns a procedure that applies the original procedure twice. For example, if inc is a procedure that adds 1 to its argument, then (double inc) should be a procedure that adds 2. What value is returned by

(((double (double double)) inc) 5)

 
(define (double f) (lambda (x) (f (f x))))
​
(define (inc x) (+ x 1))
((double inc) 1)
​x
 
3

 
(((double (double double)) inc) 5)
 
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