Functions

Updated September 10, 2023 05:00

Use function notation to make meaningful connections between expressions, tables, and other mathematical objects. Autofill tables by defining column headers with functions, or build a movable point to trace a path along a particular curve. Get started with the video on the right, then dive deeper with the resources and challenges below.

Pro-Tips

You can evaluate a function at a certain point:

$f\left(x\right)=x^{2}+3x. Evaluated at f\left(3\right) is 18. Screenshot.$

You can use the notation f(x,y), for example, to define a function with more than one variable:

$f\left(x,y\right)=x^{2}+3y. Evaluated at f\left(10,3\right) is 109. Screenshot.$

Defining a function once allows you to use this function within other functions.

$Expression line 1: f\left(x\right)=x^{2}+3x. Expression line 2: f\left(x\right)+2. Screenshot.$

You can combine multiple functions together to create a separate function or you can create a composite function.

$Expression line 1: f\left(x\right)=x^{2}+3x. Expression line 2: g\left(x\right)=5x^{3}. Expression line 3: h\left(x\right)=f\left(x\right)+g\left(x\right). Expression line 4: g\left(f\left(x\right)\right). Screenshot.$

You can use a function on points! This example scales the points by a factor of 2, and translates -2 units vertically. Explore this graph.

$Expression line 1: f\left(z\right)=2\cdot z+\left(0,-2\right). Expression line 2: Table with coordinates for quadrilateral. Expression line 3: \operatorname{polygon}\left(\left(x_{1},y_{1}\right)\right). Expression line 4: \operatorname{polygon}\left(f\left(\left(x_{1},y_{1}\right)\right)\right). Screenshot.$

Functions in Action

"The best way to learn is to do." – Paul Halmos

Graphing Challenges logo. Screenshot.

Graphing Challenges

Stretch your skills with graphing challenges.

Example graphs logo. Screenshot.

Example Graphs

Learn more by exploring example graphs.