# TI-89 won't factor or expand polynomials

• Calculators
• lxdr
In summary, when using the factor or expand functions on the TI-89 calculator, it may output a matrix with seemingly random values. This could be due to a variable, such as x, having a stored value that is being used in the calculation instead of evaluating symbolically. To fix this, either use a different variable like θ or delete the variable from the menu. Clearing the x variable has been shown to solve the issue.
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?

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!

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.

## 1. Why won't my TI-89 factor or expand polynomials?

There could be several reasons for this issue. First, check to make sure you are using the correct syntax for factoring and expanding on the TI-89. Also, make sure the polynomial you are trying to factor or expand is in the correct format. If the problem persists, try resetting your TI-89 or updating the software.

## 2. Can I factor or expand multivariable polynomials on the TI-89?

Yes, the TI-89 can factor and expand multivariable polynomials. However, the syntax for these types of polynomials may be different than for single variable polynomials. Consult your calculator's manual or an online guide for the correct syntax.

## 3. Why is my TI-89 giving me an error when I try to factor or expand a polynomial?

There could be a few reasons for this error. Check the syntax and format of the polynomial you are trying to factor or expand. Also, make sure there are no missing or extra parentheses or operators. If the problem persists, try resetting your calculator or updating the software.

## 4. How do I graph a factored polynomial on the TI-89?

To graph a factored polynomial on the TI-89, use the "factors(" command followed by the factored form of the polynomial. For example, if the factored form is (x+2)(x-3), you would enter "factors(x+2)(x-3)" into the calculator. Make sure to use parentheses around each factor and to include the variable, x in this case.

## 5. Can I use the TI-89 to solve for the roots of a polynomial?

Yes, the TI-89 has a built-in function for finding the roots of a polynomial. Use the "solve(" command followed by the polynomial expression. For example, if the polynomial is x^2+5x+6, you would enter "solve(x^2+5x+6)" into the calculator. This will give you the solutions for x in the form of a list.

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