I've got a ti 89 titanium and one of its many valuable qualities is its ability to integrate and differentiate.
However, just recently, it have not been functioning correctly. When I try to calculate indefinite integrals or derivatives, my calculator returns a number instead of an expression.
keystrokes:[2nd] [∫] [X] [,] [X] [)]
keystrokes:[2nd] [d] [X] [^]  [,] [X] [)]
The calculator should be returning expressions involving the variable in question. I have no equations in the y editor, no programs that I have created or are aware of that might cause this and I have tried removing all the batteries with the idea in mind that it might reset the defaults. No luck.