I’m a big fan of Wolfram Alpha. Fred Feldon has designed a series of worksheets that allow students to explore various concepts using Wolfram Alpha. I like the idea of students exploring some of the more abstract mathematical concepts on their own.
Fred’s Rational Expression Exploration is posted here.
I really liked Fred’s work, but wanted the rational expressions to look more like rational expressions so I modified it slightly. Here’s my Word document of the same activity: Rational Functions WA Activity 8 Modified