The idea of smoothing a function is an important concept in
signal processing. If f is a function and dx is some small number, then the smoothed version of f is the function whose value at a
point x is the average of f(x - dx), f(x), and f(x + dx). Write a procedure
smooth that takes as input a procedure that computes f and returns a procedure that computes the smoothed f. It is sometimes valuable to repeatedly smooth a function (that is, smooth
the smoothed function, and so on) to obtained the n-fold
smoothed function. Show how to generate the n-fold smoothed
function of any given function using
repeated from exercise 1.43.