## Saturday, July 12, 2014

### Interactive Intro to Domain and Range

One of my favorite things about Common Core is the opportunity to learn new ways to introduce content. I have been teaching high school for 7 years, so I haven't had the chance to teach with too many books.  With common core and the impending adoption of new materials, I am finding new ways to teach almost weekly!

I had a chance this week to play around with domain and range using the TI Inspire.  I can't take credit for most of the ideas below, but this introduction is too good not to share!  Check out the Texas Instruments website for free worksheet downloads that go with domain and range presented in this manner, plus many other topics.  The worksheets go with TI calculator activities, but you can still get great ideas from them if you don't have access to the technology.

Drag the gray point in the presentation below over points A, B, C, D and E.  Watch as the domain and range values appear on the axes.  To try a different problem set, hit "clear domain and range", drag each point to a new location, and repeat the activity.

Can you arrange the points so that the domain is {-2,3,5} and the range is {1,2}?  This question has multiple solutions and will give students the opportunity to discuss the mathematics and check answers in real time. They are also practicing with multiple representations.

Students can find domain and range of a line segment below by dragging point C.  Again the domain and range values appear along the axes.  To try a new problem hit "clear trace" and drag the endpoints to a new location.

Can you find the line segment that has domain greater than or equal to -3 and less than 4, and range greater than -1 and less than or equal to 3?  Insert inequality statements into these problems to help students practice with the multiple representations used in this context.

For the presentation below drag point A to create a relation.  Can you graph the relationship with domain and range described below?  Is your relation a function?

To show domain and range for a specific function, enter the function into the input box below. Change the left and right limit of the function to make it piecewise, or to see what the domain and range are for the the function itself change the limits to values that are not on the screen below.  (So -6 and 8 will work).

Links you may find useful:

Geogebra Tools from Making Math Visual blog.

Geogebra Series II: Transforming a Graph With Sliders