Solution 29131: Calculating nth Roots Using the TI-Nspire™ Family Products.
How do I calculate nth roots (cubed roots, fourth roots, etc) using the TI-Nspire family products?
To calculate nth roots using the TI-Nspire family products, follow the example below. Texas Instruments recommends all TI-Nspire family users update the handheld and computer software to the latest operating system. More information on the latest operating system can be found at the TI-Nspire family latest software website.
Example: Calculate the cubed root of 343
• Press [home]  to insert a “New Document”. If prompted to save the existing document, choose “Yes” or “No”. Press  or [enter] to insert the “Calculator” application into the New Document.
• To select the nth root template, press the math template key which is located directly to the left of the  key. The nth root template is the 4th option on the 1st row. If using a Clickpad family handheld, press [ctrl] [n√x].
• In the top box, input 3 and press [tab] to scroll to the bottom box.
• In the bottom box, input 343 and press [enter]. The solution of 7 should be displayed.
NOTE: To calculate fourth roots, fifth roots, etc, simply change the value in the top box.
Please see the TI-Nspire family guidebooks for additional information.