Solution 13482: The xRes Setting is Grayed Out and Cannot be Changed on TI-89 Titanium or Voyage™ 200 with OS Version 3.10.
How do I change the xRes setting on the TI-89 Titanium or Voyage 200?
The solution lines have been affected in the new discontinuity detection setting put into OS 3.10. If it is engaged (the default setting), then xRes will be set automatically by the calculator. To turn it off:
1) Go to the Window Screen.
2) Press F1 and choose 9:Format...
3) Go down to Discontinuity Detection and choose Off.
4) Press [Enter] to confirm the selection, and then [Enter] again to save the setting.
The xRes setting should now be able to be modified.
For additional instructions, refer to the online guidebook for your calculator.