When working with functions it’s important to understand function notation, or how the function is written. When writing a function there are two important aspects, the name of the function and the name of the independent variable. The name of the function is usually the letter f, but it can be any letter. See the following figure show how an example of function notation.
The above function is read f of x, with f being the name of the function and the x being the name of the independent variable.
Now it is possible to have more than one variable in a single function. To indicate that a single function has more than one variable in it, in the space inside the parenthesis you place all of the variables, separated by commas. For example, if a function, h, has four variables: w, x, y, and z would be written as:
To indicate that we are looking at a specific point in the function simply replace the variable inside the parentheses with the number we are looking at. This would be written as:
What this means is that you take the function, and replace all of the independent variables with the number 5.