The TI Nspire CAS is almost exactly the same as the regular Nspire, however with the added benefit of a “computer algebra system”, or CAS. The CAS capability allows a user to perform symbolic algebra which can greatly reduce the time spent on the menial aspects of solving a problem. The Nspire CAS can:
• Symbolically evaluate integrals and derivatives
• Simplify and solve symbolic equations and expressions
• Solve symbolic differential equations
• Evaluate limits of functions
• Perform symbolic matrix algebra
The TI Nspire series have interchangeable keypads, the CAS can be fitted with a “clickpad” or a “touchpad”. It should be noted that the touchpad model is NOT in fact a touchscreen calculator; instead, it has a laptop-style touch pad which can be used to maneuver the cursor. If you own or buy the keypad version, you can buy the actual touchpad section separately for $10-$20 and attach it to the TI Nspire.
If you are unsure whether you should buy the TI Nspire or the TI Nspire CAS, it may be a wise decision to buy the CAS version. The Nspire CAS does everything that the standard Nspire does but it also has the added benefit of the powerful computer algebra system. However, it should be noted that only the standard TI Nspire can be fitted with the TI-84 keypad, so be sure to consider this before making any purchase.
Once again, the biggest issue with the TI-Nspire CAS is the steep learning curve. It can take some time to learn how to properly use the calculator, however once mastered, the Nspire will be an indispensable tool in your mathematical education and research.