I recently found another calculation that I would consider reasonable for my students to perform that their calculators cannot. On my Calc II students’ final exam, I asked them to evaluate the infinite series \(\displaystyle \sum_{n = 1}^\infty \frac{4}{(n + 3)(n+5)}\). As a hint, I told them to rewrite in telescoping form using partial fractions. However, the TI-89 cannot evaluate this series. Since it’s hard to take a good photo of the calculator screen, I’ve instead included a screen shot of the TI-Nsipre CAS iPad app.

## One Reply to “Brains over calculators, part 2.”

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Cool! I didn’t realize TI made a calculator app. I see that it’s only for iPad and costs $30 though :-/