Hmm. I plugged that integral into Mathematica, and it spit out the exact answer: And I have Mathematica 4, an old version. Perhaps your TI doesn't have a robust enough algorithm to handle an integral like that. This goes to my usual modus operandi: use calculators for less-intensive quick computations. I have a TI-85, and I've never needed anything beyond that for a calculator. But if you want to do any serious symbolic work, use Mathematica, and if you want to do any serious numerical work, use MATLAB. That's my opinion.