SICP Exercise 1.42

Question

Let \(f\) and \(g\) be two one-argument functions. The composition \(f\) after \(g\) is defined to be the function \(x\mapsto f(g(x))\). Define a procedure compose that implements composition. For example, if inc is a procedure that adds 1 to its argument,

((compose square inc) 6)
49

Answer

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

(define (compose f g)
  (λ (x) (f (g x))))

((compose square inc)  6)

Result:

49