argument error

ralicesnow · Joined: 27 Sep 2007 Posts: 1

when I use the expand(, factor(, or propFrac( using a variable, for example.
factor(x^2+1) or expand((x+y+1)^2,y)
(these are taken straight out of the TI-89 guidebook, I get an argument error. factor and expand work fine when i use constants though, such as expand(25).
Any idea whats wrong?

Also, does the TI-89 have a questionmark (?) key?

mellamokb · Joined: 10 May 2007 Posts: 100

Hi ralicesnow,

Welcome to TI-89.org forums.

There is nothing wrong with your function call. You probably have a function or program stored under the variable "x" or "y". Try executing the "Clear A-Z" command under the "Clean Up" menu (F6).

You can find special characters like "?" under the "CHAR" menu, which is [2nd]+[PLUS] on the TI-89T. The third submenu, "Punctuation", has a question mark as the 8th entry.

Hope this helps.

~ mellamokb