<p>Is your TI-Nspire a TI-Nspire CAS? Because if not, it is more analogous to the TI-84 than the TI-89. You are allowed 2 calculators on the ap exam; I believe the usual strategy is to have both a symbolic calculator for tougher problems and a non-symbolic one for quicker problems (time is a factor on the exam, after all). If a problem takes a while to be solved or graphed you can also use the other calculator. So yeah, if you don’t have the TI-Nspire with CAS, buy an 89 or a TI-Nspire with CAS. If you do, combined with your 84 you have nothing to worry about.</p>
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As I recall, the calculator portion of the exam included some integrals that we were never taught how to do by hand and which would have likely taken hours to calculate to the required level of accuracy even if we knew the right approximation methods, so yeah… a calculator is essential.</p>
<p>The main advantage of symbolic calculators are the ability to give you symbolic answers (they will do long division for you, and you can ask them to take a derivative or an integral and they will give you the expression instead of just being able to ask them for an approximation at a certain point or for a certain definite range).</p>
<p>That being said, the TI-89 Titanium is God’s gift students of the quantitative disciplines (mathematics, physics, statistics, and engineering).</p>