Online Graphing Calculator (there is a free app for the phone if you would like to download) 

The APP WILL NOT be allowed to be used in the classroom but can be a useful resource when at home.  

This site has useful videos to help explain any math concepts from K-12.  If you need extra explanantion or cannot remember what we did in notes, search this site. 

Login in page for Pre-Calculus/Trigonometry online textbook