HP Prime polynomial long division



#2

If i calculate (x^3+x):(x^2+3) manually via polynomial long division the result is x-(2x)/(x^2+3)

How can i get this result with the HP Prime?


#3

Quote:
If i calculate (x^3+x):(x^2+3) manually via polynomial long division the result is x-(2x)/(x^2+3)

How can i get this result with the HP Prime?

In CAS mode, use partfrac. Access: Toolbox, CAS, 1. Algebra, 6. Partial Fraction

Hope that helps.


#4

Great, thank you!

#5

A further question: What is the difference between partfrac and cpartfrac?


#6

Quote:
A further question: What is the difference between partfrac and cpartfrac?

cpartfrac is the complex counterpart of partfrac

Example:

cpartfrac((x^3+x)/(x^2+3)) returns x - 1/(x+i*sqrt(3)) - 1/(x-i*sqrt(3))


#7

o.k.

#8

Thanks. Does CAS Settings / Simplify need to be set to NONE or MINIMUM for this result? Appears that MAXIMUM will show the rational being "recomposed" as x^3+x : x^2+3.

Best


#9

Yes, it will recombine them in your version unforuntately. Note that this will all work much better in the future. There is a reason we did not put it to anything but "none" by default in the initial release. :-)

TW


#10

Hi Tim,

A related issue. I want to expand and then recombine a symbolic polynomial to group the coefficients by powers, i.e.

(a-x)*(b-x) ---> a*b - (a+b)*x + x^2

If I enter this expression in CAS with simplify set to maximum in the settings the result I get is:

a*b - a*x - b*x + x^2

where the coefficients are not grouped for the power of x^1.

Is there some way to do this ?


#11

I found a solution in the CAS function "symb2poly".

symb2poly ((a-x)*(b-x)) ---> [1 -a-b a*b]


#12

real collect

Poly:= (a-x)*(b-x)
Var:= x

sum( coeff( Poly, Var ) .* seq( Var^k, k, degree( Poly, Var ), 0, 1 )

#13

Quote:
In CAS mode, use partfrac.

To see the results of polynomial long division, propfrac is more what he was looking for.

partfrac(((x^3+2*x²+3*x+4)/(x²-9))) returns the partial fractions
x+2+(29/3/(x-3))+7/3/(x+3)

while

propfrac(((x^3+2*x²+3*x+4)/(x²-9))) returns the proper fraction:
x+2+(12*x+22)/(x²-9)

-wes


#14

"propfrac" is exactly the command i need. It's too bad that "propfrac" is not in CAS-Menü.


#15

quo, rem and quorem are the CAS instructions to perform polynomial division.


Possibly Related Threads...
Thread Author Replies Views Last Post
  Polynomial program Michael Carey 12 458 11-20-2013, 08:43 PM
Last Post: CR Haeger
  HP Prime: Long integers (continued) Helge Gabert 2 200 11-07-2013, 11:24 AM
Last Post: Helge Gabert
  HP Prime: Pass "Long" Integers to a Program Helge Gabert 6 360 11-03-2013, 01:12 PM
Last Post: Helge Gabert
  [HP-Prime xCAS] Review Polynomial Tools + BUGs + Request CompSystems 0 137 09-05-2013, 12:53 PM
Last Post: CompSystems
  Matrix Characteristic Polynomial - Reloaded. Ángel Martin 12 470 08-22-2013, 05:33 PM
Last Post: Thomas Klemm
  Why does PEMDAS do multiplication and division before addition and subtraction? Don Shepherd 12 514 07-31-2013, 10:59 AM
Last Post: robert rozee
  A very long HP-17BII equation Gerson W. Barbosa 22 799 04-19-2013, 12:37 AM
Last Post: Gerson W. Barbosa
  A long WP-34S night Siegfried (Austria) 10 432 04-16-2013, 02:11 AM
Last Post: Siegfried (Austria)
  HP-25 left on for a long, long, while Matt Agajanian 12 457 04-10-2013, 11:33 PM
Last Post: Steve Leibson
  New Blog Post: Length of a Polynomial Segment Eddie W. Shore 1 159 01-17-2013, 08:56 PM
Last Post: Namir

Forum Jump: