TI-89 won't factor or expand polynomials

[lxdr]

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?

 

[cbasst]

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.

 

[justsomeguy]

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.

 

[lxdr]

Clearing the x variable worked. Thanks for your help!

 

[LudusRex]

I understand your frustration with the unexpected output from your TI-89 calculator when using the factor or expand functions. It is important to note that calculators, like any other technology, are not infallible and can sometimes produce unexpected results.

In this case, it seems like your calculator may be set to a different mode or function than what you are trying to use. The output you are receiving is not a result of factoring or expanding the polynomial, but rather a matrix calculation. This could be due to the calculator being set to a matrix mode or using a matrix function instead of the desired polynomial function.

To fix this issue, I would recommend checking the mode settings on your calculator and ensuring that it is set to the appropriate function for factoring or expanding polynomials. You may also want to consult the user manual for your calculator or reach out to the manufacturer for further assistance.

In addition, it is always a good idea to double check your input and make sure that you are using the correct syntax for the function you are trying to use. This can also help to avoid unexpected results.

Overall, while technology can be a helpful tool in scientific research and calculations, it is important to understand its limitations and potential for errors. I hope this helps to resolve your issue and I wish you success in your future calculations.