How do you get a function of a function?

The average of a set of numbers is equal to the sum of those numbers divided by the number of numbers. So, one might say that the average function is equal to the sum function divided by the count...

The word non-function can mean practically anything, a variable, for example. int fun (int x) { return x+10; } int nonfun= 32;

The parent function of the exponential function is ax

No. A simple example of this is y = x2; the inverse is x = y2, which is not a function.

In mathematics the difference between a function and a relation is that each X-value in a function only has a single Y-value.