MaplePrimes - Questions and Posts tagged with coeff

Why does evala cause an error?

njschwar — Thu, 28 Mar 2013 18:38:13 Z

In the following script, I am trying to understand why evala returns an error. It returns

Error, (in evala/Reduce/nf/indep) invalid arguments to coeffs

in a couple of places. I tried, and I can get around the errors by doing it a complex way, but it seems like I'm just not using evala correctly. Perhaps someone can comment? I'd very much appreciate it.

Correlation coefficient for system of nonlinear differential equations and data

kierstejn — Wed, 12 Dec 2012 19:35:44 Z

Hey guys..

I need some help on determining the correlation coefficient between my data points for an Influenza epidemic and the SIR model, with my estimated parameters Beta and Alpha. The initial conditions for the equations are defined at the beginning of my worksheet:

SIR_model.mw

Hope someone can help me ;)

How do I extract the corresponding variables given the list of coefficients ?

satya123999 — Sun, 04 Nov 2012 01:38:11 Z

I have a multivariate polynomial equation, in that somehow I know the coeffcients, using this information, I want to extract the variables. This will be the opposite of coeffs function.

for e.g. I have 3*x3 + 5*x4

Given 3 and 5, I want to extract x3 and x4.

Thanks in advance.

Satya

Solve equation of 13th order with symbolic coefficient

dritsaev — Tue, 19 Jun 2012 08:54:23 Z

Hello,

i want to solve the following for q[b], theta is a symbolic coefficient. When I use the solve command it produces a RootOf that i cannot handle by using either allvalues or evalf. I can't use fsolve since there is theta

How do i solve this list

Ronan — Tue, 22 May 2012 20:05:38 Z

I have Zipped 2 equations together to equate their equivalent Coefficients. I now need to assign solve the list fot each value of N (1...9) How do I get Maple to do this reliably for the list as N 1..9 does not necessarily occour in sequence.

Unable to compute coefficient

mgu — Mon, 09 Apr 2012 03:57:00 Z

Hi, I am trying to compute the coefficient of a polynomial as follows:

a:=(1/11520)*(4518-4320*r^(2*n)-5760*_C1*n^4*r^2-97920*_C1*n^2*r^2-97920*_C1*n*r^2-40320*_C1*n^3*r^2+2020*r^6*n^3+1500*r^6*n^2-1440*r^(2*n+6)+60*r^8-2880*r^(2+2*n)-720*r^4-100*n^5-339*n^2+3018*r^2+4560*r^(2+2*n)*n-240*r^(2*n+4)*n^2-480*r^(2+2*n)*n^4+50*r^8*n-130*r^8*n^4-270*r^8*n^3-170*r^8*n^2-20*r^8*n^5+480*r^(2*n+6)*n+480*r^(2*n+6)*n^3-480*r^(2*n+6)*n^2-1680*r^(2+2*n)*n^3+160*n^5*r^6-102*n*r+320*r^2*n^5+1783*r^2*n^4...

Dividing a multivatiate polynomial

Ronan — Fri, 30 Mar 2012 20:58:20 Z

I have a rather large multivatiate polynomial "Dtest" I need to divie it by a cubic poly "DGm" using rem and quo. Both are determinants multiplied out, both given below. Have spent the past 2 nights trying to sort, collect, expand, equate coefficients plex groebner etc. Am trying to collect up all the powers of c₃ but cant anything to work. even expand doesn't fully expand "Dtest". If I set c₁ and c₂ to 1 things are...

Why is not the coefficient non-zero?

mgu — Sun, 25 Mar 2012 00:50:04 Z

I have the following lines of code:

W:=sum((k^(2*i))*sum((e^(j))*w[i,j](r,t),j=0..2),i=0..2);

P:=sum((k^(2*i+1))*sum((e^(j))*w[i,j](r,t),j=0..2),i=0..2);

for c from 0 to 2 do

for d from 0 to 2 do

rw[c,d]:=coeff(coeff((k/(2*r))*(diff(W,r)*diff(P,t)-diff(W,t)*diff(P,r)),k,2*c),e,d)

end do

end do;

I mean to compute the coefficients in front of powers of e inside...