HP Prime: How would you factor polynomials?

[Speedstang]

Sorry if I'm missing something obvious, it's my first graphing calculator. Anyways, I know I can use CAS mode to multiply polynomials with the simplify button, but this doesn't factor them out. How would I factor something like x^4 - 6 x^3 - 31 x^2 + 216 x - 180 = 0 on it?

[Maké · Accepted solution]

Hi!, Speedstang:

You needed read, the User Guide, CAS menu, page 361, from ... http://support.hp.com/us-en/product/HP-Prime-Graphing-Calculator/5367459/model/5367460/manuals/

See, the right column and select 4 Factor and OK; then, you have factor(). Into the parenthesis, write the polinomy and press ENTER key.

You see, in upper, mode approximate and lower, in mode exact.

With, Wolfram Alpha ...

[Speedstang]

Well, uh, I feel dumb. xD

Thanks for the help, and I need to go through the user guide 😕

[Maké]

Hi!, Speedstang:

The User's Guide, is ideal for begineers, but many examples, and solution's, you can write here and other, very good site ... http://www.hpmuseum.org/forum/index.php

In the same site, you can read guides, from ... http://www.hpmuseum.org/forum/thread-818.html

Too, in www.hpcalc.org

[natiemuller]

I am not able to factor anything on polynomials or binomials on the HP PRIME??? I did the steps suggested and its not factoring them completly out. It just gives me a zero as the answer...I cant find anything online of a solution to this problem.

[Maké]

Hi!, @natiemuller:

Can you, explained, with one example, where, have the problem ?.

You can see, this video for factoring trinomial ...

Technology in College Algebra - Factoring Trinomials - HP Prime ...

https://www.youtube.com/watch?v=mxwyTiPUHH8

[Tim_Wessman]

You are most likely in the "HOME" screen. This is always going to behave like a "normal" calculator and evaluate everything down to a single number. Press the CAS button to open the CAS screen, and try it again. I suspect it will work fine for you after that.

If this was the case, please take a look at the "quick start guide" that came with your calculator. The section "

Computer algebra system (CAS)" should give you a short overview and will be helpful.

If this doesn't work for you after going to the CAS screen, you'll need to provode more details for anyone to be able to help you.

[Jan_D]

Hello Maké,

Interesting to see that the approximate result in message 2 is completely wrong.

Instead of a factor (x-1) it gives a factor x.

[Jan_D]

I observe a very strange behaviour of the commands: factor, solve and fsolve.

Let’s consider the command: factor.

When all coefficients of the polynomial are integers it gives the correct answer.

When I replace 31 by 31.0 it gives a wrong answer: the factor (x-1) is replaced by x.

But when I replace 31 by 31.01 it gives a correct answer again.

So there is a bug for the cases 31. , 31.0, 31.00 and so on.

[Maké]

Hi!, @Jan_D:

If you change in the Format to Std, you obtein irreducible factorization ...

In, Wolfram Alpha ...