Before I bought a TI-89 Titanium, I had used a TI-83 Plus for four years. After taking calculus and learning about limits, derivatives, integrals, infinite series, Taylor series, differential equations, and multivariable functions, I decided that I would look for a calculator which was capable of symbolic computation. After analyzing my options, I decided on a TI-89 Titanium. The TI-89 Titanium is able to expand polynomials, factor polynomials, and do all of the calculus techniques that I mentioned -- symbolically and numerically. One of the other things I found helpful was the TI-89 Titanium's...