TI-89 won't factor or expand polynomials

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  • Thread starter Thread starter lxdr
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    Polynomials Ti-89
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Discussion Overview

The discussion revolves around an issue with the TI-89 calculator where users encounter unexpected outputs when attempting to factor or expand polynomials. The focus is on troubleshooting the calculator's behavior in relation to variable storage and symbolic evaluation.

Discussion Character

  • Technical explanation, Problem-solving, Homework-related

Main Points Raised

  • One participant reports that using the factor or expand functions results in a matrix output instead of the expected polynomial result.
  • Another participant suggests that the issue may arise from a variable (x) having a stored value, which could lead the calculator to evaluate expressions incorrectly.
  • A later reply confirms that clearing the variable x should resolve the issue.
  • One participant notes that their previous response was missing, indicating potential issues with the forum or posting process.

Areas of Agreement / Disagreement

Participants generally agree that the problem is related to the variable x potentially having a stored value, and that clearing this variable can fix the issue. However, the initial cause of the unexpected matrix output remains unverified.

Contextual Notes

There is an assumption that the user is familiar with the calculator's functions and the process for clearing variables. The discussion does not explore the implications of using different characters or the broader context of symbolic computation.

Who May Find This Useful

Users of the TI-89 calculator, particularly those encountering issues with polynomial functions and variable storage.

lxdr
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When I use the factor or expand functions on my TI-89 it outputs a matrix with values that are seemingly coming from no where. For example, if I ask my calculator to expand (3-x)^2 it gives the matrix [45, 12; 12,13]. Why is it doing this? How do I fix it?
 
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I don't know what the problem is, but is it possible that you have something (maybe a matrix?) stored in the variable x? If x has something stored in it, the TI-89Ti evaluates the expression as though the stored value were there in place of x rather than evaluating the expression symbolically. If x does have something stored inside it, try using a Greek character such as θ (available using the diamond button and selecting the ^ key) or anything else you can find in the 2nd->char->Greek menu. An alternative to using a Greek character would be to delete the variable x from the 2nd->Var-Link menu. Let me know if that helps.
 
I got notified of a response to this and see my own response is just not here / has disappeared. So.. trying again.. clearing out the X var should do the trick.
 
Clearing the x variable worked. Thanks for your help!
 

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