If you don't have a graphing calculator a home here are a few options for you.
To download a version of the TI 83(which we use in class) click on this link.
If you have a Droid phone and want to download an app for the TI 83, click on this link.
And lastly if you want to use an online version, look at the link along the right of this page.
Remember it is very important that you have access to a graphing calculator to do work at home.