Re: Creation and evaluation of polynomials

• To: mathgroup at smc.vnet.net
• Subject: [mg89453] Re: Creation and evaluation of polynomials
• From: dh <dh at metrohm.ch>
• Date: Tue, 10 Jun 2008 03:39:00 -0400 (EDT)
• References: <g2j05j\$510\$1@smc.vnet.net>

```
Hi,

could you please explain how {1,0,0,0,1,0,1} is related to p^5 + 3p^2?

Perhaps, you mean {0, 0, 3, 0, 0, 1}, what I could understand. If so,

there is no need to convert to a string:

p={0,0,3,0,0,1};

pol[p_,var_]:= p.Table[var^i,{i,0,Length[p]-1}];

pol[p,x]

hope this helps, Daniel

jmgomezgoo at gmail.com wrote:

> Hi!

>

> Image we have a function that create a Polynomial:

>

> polynomial[{1,0,0,0,1,0,1,}] -> p^5 + 3p^2

>

> And we want to calulate roots and the derivate of this polynomial.

>

> I try with ToString[polynomial[{1,0,0,0,1,0,1}]] in order to use

> convert the polynomial expression to string first and later use

>

> ToExpression[]

>

> and calculate roots

>

> D[ToExpression[ToString[polynomial[{1,0,0,0,1,0,1}]], x]

>

> like the next examples:

>

> D[ToExpression["x^2+2x"], x]

>

> or

>

> NSolve[ToExpression["x^2+2x==x"], x]

>

>

> But ToString erase ^ symbol.

>

> Somebody knows how to solve it?

>

>

> Warm regards

> -jm

>

>

>

--

Daniel Huber

Metrohm Ltd.

Oberdorfstr. 68

CH-9100 Herisau

Tel. +41 71 353 8585, Fax +41 71 353 8907

E-Mail:<mailto:dh at metrohm.com>

Internet:<http://www.metrohm.com>

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