# Questions tagged [coefficients]

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### Coefficients of a multivariate polynomial

Let's say I have the polynomial $x+2y+3xy \in \mathbb Q[x,y]$ or $x_1+2x_2+3x_1x_2 \in \mathbb Q[x_1,x_2]$, that is x+2y+3xy or ...
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1 vote
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### Nonlinear Model Fit - Force a Constrain

I am trying to achieve the best fit for a non linear model, yet I need to ensure that certain coefficients return as positive values. I have been looking for similar questions but I have found nothing ...
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### Get coefficient of a symbolized symbol in a sum that involves other symbolized expressions

My mathematica notebook begins with symbolizing all expressions of the form $x$ subscript an integer, "$x_k$", ...
• 155
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### Extracting the constant term

Finite difference problem There are a large number of variables, interacting at most five at a time. A sample term is: How to extract the constant term? In this example, the constant term is -1/4.
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1 vote
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### How to write code for SeriesCoefficient to work for non integral coefficients?

I have a function of $r$ which I expand at $\infty$ using Series. It is a complicated and messy function, with a parameter $0 \leq \epsilon < 1$. After expansion,...
1 vote
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### How to evaluate an Integral which has Interpolating functions

I am trying to evaluate an Integral which has products of Interpolating functions inside, using NIntegrate command. It gives a wrong answer. The code that I used for performing this task is given ...
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### Finding Coefficients in a Perturbation Problem related to Chaotic Dynamics

I am trying to reproduce the results from this paper: Chaotic dynamics of a suspended string in a gravitational background with magnetic field I am currently stuck with finding the coefficients. First ...
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### Plotting of a polynomial function via two approaches

I am trying to plot a polynomial via two approaches: Take CoefficientList of the polynomial and then take InternalFromCoefficientList, and finally replacing the value of the free parameter with a ...
70 views

### Series development of laurent in a defined domain

I am trying to correct some bills for laurent series with mathematica, but the output I am getting at the moment is not the best. For example, I have this function $$\frac{1}{z^2 + 9}$$ to develop at ...
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### Create a general polynomial function [duplicate]

I search for a simple procedure to create a polynomial function with unknown coefficients. For example if I asked for the most general polynomial of two variables 'x' and 'y', of second degree, it ...
1 vote
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### Replace coefficients in a polynomial

I want to replace the coefficients of a polynomial by new coefficients. For example, my polynomial of variable 'r' is in the picture I want to replace the coefficients with 'a subscripts' similar to ...
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1 vote
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### Coefficient works on $\pi$, $x$ and $x^2$, but not on $\pi ^2$

Consider (\[Pi] + 2 \[Pi]^2 + 3 x + 4 x^2) Executing ...
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1 vote
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### Finding coefficients where part of the coefficient may appear in the terms

A minimal example is given below. My goal is that given a algebraic expression such as: expr = a^2 + a b + a^3 b + 2 a^2 b^2 + a b^3 I'm trying to find a command, ...
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### Take coefficients of the variable from a Matrix

I have a question how can I take coefficients of the variable from a matrix? for example; I have a matrix such as: A={{2a,3b,4c},{4d},{1a,1e}} variable is {a,b,c,d,...
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### How to collect coefficients that has summation in ODE

I have the following equation, equation= x''[t]+a*x'[t]+b*x[t]+c*y[t]+d*u[t]+e*v[t]+Sum[f[i]*x[t]+g[i]*u[t]+h[i],{i,1,n}]+k When I collect the coefficient of each ...
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### Behaviour of Coefficient[] for negative exponents in rational expressions

I've observed a puzzling behaviour of Coefficient[] for negative exponents and I'm wondering if I was always just relying on undefined behaviour or if there is a ...
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1 vote
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### Finding polynomial coefficients returns Tag Plus is Protected [closed]

I'm trying to find the coefficients of a polynomial $P(x)$. Please see following equation. $$P(x+2)+P(x-2)=2x+8$$ CoefficientList[P(x+2)+P(x-2)=2x+8,P(x)] However ...
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1 vote
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### Extracting coefficients from a sum of exponential functions

I'm dealing with a sum of exponential functions with different exponents ...