Traditionally, functions are referred to by the letter name f, but f need not be the only letter used in function names. The following are but a few of the notations that may be used to name a function: f (x), g(x), h(a), A(t), ...
Note: The f (x) notation can be thought of as another way of representing the yvalue in a function, especially when graphing. The yaxis is even labeled as the f (x) axis, when graphing. Often times,
mathematics has a variety of ways to say the same
thing.
To evaluate a function, simply replace (substitute) the function's variable with the indicated number or expression.
