Discover MakerZone

MATLAB and Simulink resources for Arduino, LEGO, and Raspberry Pi

Learn more

Discover what MATLAB® can do for your career.

Opportunities for recent engineering grads.

Apply Today

Thread Subject:
Simple polynomial representation question

Subject: Simple polynomial representation question

From: theconster@gmail.com

Date: 15 May, 2009 03:35:00

Message: 1 of 6

Hello,

I have just posted a question about the sylvester MATRIX (and found an earlier answer that I understand a bit) but anyway, I realised I don't know how to represent the polynomial i need to in a way that I can input it on MATLAB.

The polynomial is just:

p(x) = a(1)*x^n + ... + a(n)*x + a(n+1)

how do I input this to MATLAB? I know it is equal to:

a_n x [infinite product](x - alpha_i)

where alpha_i is a root of p(x)

please help!

thanks in advance.

Subject: Simple polynomial representation question

From: Matt Fig

Date: 15 May, 2009 04:05:02

Message: 2 of 6

Type this at the command line:

docsearch polynomials

Now sit back and read ;-)

Subject: Simple polynomial representation question

From: theconster@gmail.com

Date: 15 May, 2009 04:32:42

Message: 3 of 6

Hi, I realise now that my question is rather obvious and I even knew how to do it, in the basic sense.

What I meant to ask was, how do I create the vector with the entries a(1) through to a(n+1)?

Subject: Simple polynomial representation question

From: Bruno Luong

Date: 15 May, 2009 06:24:02

Message: 4 of 6

"theconster@gmail.com" <theconster@gmail.com> wrote in message <15637332.105701.1242361992707.JavaMail.jakarta@nitrogen.mathforum.org>...
> Hi, I realise now that my question is rather obvious and I even knew how to do it, in the basic sense.
>
> What I meant to ask was, how do I create the vector with the entries a(1) through to a(n+1)?

Read the GETTING STARTED section. This basic array assign (and few more important things) should be understood before you start to work on a real project.

http://www.mathworks.com/access/helpdesk/help/techdoc/learn_matlab/bqr_2pl.html

Bruno

Subject: Simple polynomial representation question

From: theconster@gmail.com

Date: 15 May, 2009 06:52:19

Message: 5 of 6

I have read and understood all of this getting started section, my problem is just that these examples all use numbers, I am dealing solely in unknowns, and an unknown size of vector.

Do i need to work with the symbolic math toolbox? and is there a convention for subscripting so that I can write, for e.g. a = [a_(1):a_(n+1)]

Subject: Simple polynomial representation question

From: Bruno Luong

Date: 15 May, 2009 07:11:01

Message: 6 of 6

"theconster@gmail.com" <theconster@gmail.com> wrote in message <1919759.105934.1242370369729.JavaMail.jakarta@nitrogen.mathforum.org>...
> I have read and understood all of this getting started section, my problem is just that these examples all use numbers, I am dealing solely in unknowns, and an unknown size of vector.
>

Unknown are a human concept, not programming language. "Unknown" must be solved at one point using fsolve, fzero, polyfit, fmincon, fminun, linprog, backslash... or symbolic toolbox. Matlab can solve and only use solved unknown, which is in fact known after solving...

Bruno

Tags for this Thread

No tags are associated with this thread.

What are tags?

A tag is like a keyword or category label associated with each thread. Tags make it easier for you to find threads of interest.

Anyone can tag a thread. Tags are public and visible to everyone.

Contact us