Solution 30371: Calculating Double Limits on the TI-Nspire™ CAS Family Products.
How do I calculate double limits on the TI-Nspire CAS family products?
To calculate double limits using the TI-Nspire CAS family products, the "Calculator" or "Scratchpad" application and "Limit" function must be used. Follow the steps below to calculate the double limit for the example function.
Example: Find the double limit of the function (x+1)/(y+5) as x approaches 3 and y approaches 2.
1) Press [home] and select the Calculator or Calculate (from the Scratchpad) application.
2) Press [menu]   to select the Limit function. The Limit template is displayed.
3) The handheld will prompt for the variable in the limit. From the example function, input x and press the [right arrow] key.
4) The handheld will prompt for the value that the limit will approach. Input 3 and press the [right arrow] key.
5) Repeat the 3rd and 4th steps above using y as the variable in the limit and 2 for the value the limit will approach.
6) The handheld will prompt for the direction of the limit (left, right, or both). For this example, leave it blank and press the [right arrow] key.
7) Input the example function (x+1)/(y+5).
8) Press [ENTER]. The handheld should return .571429 as the solution.
For more information on how to use the TI-Nspire CAS handheld, please see the TI-Nspire CAS guidebook.