First, it is useful to give a function a name. The most common name is "f", but you can have other names like "g" ... or even "marmalade" if you want. But let's use "f":

f(x)

You would say "f of x equals x squared" what goes into the function is put inside parentheses () after the name of the function: So f(x) shows you the function is called "f", and "x" goes in And you will often see what a function does with the input: f(x) = x2 shows you that function "f" takes "x" and squares it. Example: with f(x) = x2:

name.The most common name is "

", but you can have other names like "f" ... or even "g" if you want.marmaladeBut let's use "f":

You would say

"f of x equals x squared"what goes

intothe function is put inside parentheses () after the name of the function:So

shows you the function is called "f(x)", and "f" goesxinAnd you will often see what a function does with the input:

shows you that function "f(x) = x2" takes "f" and squares it.xExample: with

f(x) = x2:- an input of 4
- becomes an output of 16.

In fact we can writef(4) = 16.