Functions Test Topics

We’ll use the questions on the Functions Diagnostic Test to illustrate the conventions of functions.

DON’T BE AFRAID OF FUNCTIONS

There’s nothing inherently  difficult   about   functions.  There   are not a   lot of  formulas    or

theorems    to  remember.   Getting comfortable with    functions   just    means   understanding   the

symbolism   and conventions.

WHO’S AFRAID OF FUNCTIONS?

Lots of students are afraid of functions. But there’s nothing especially difficult about them. They just
look scary. Once you “get” the conventions, you’ll never be afraid of functions again. Here’s a quick
and painless review of the basic things you need to know about functions.

A function is a process that turns a number into another number. Squaring is an example of a
function. For any number you can think of, there is a unique number that is its square. The
conventional way of writing this function is:

f(x)    =   x^2

When you apply the function to some particular number, such as −5, you write it this way:

f(−5)

And to find the value of f(−5), you plug x = −5 into the definition: