# Questions tagged [coefficients]

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### Extracting matrix coefficients from multivariate matrices

Suppose we have a multivariate polynomial matrix $P(\mathbf x) = \sum_\alpha A_\alpha\mathbf x^\alpha$ (in multi-index notation) where the $A_\alpha$ are constant coefficient matrices. I am looking ...
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### How can I extract a matrix and vectors of coefficients from this quadratic expression?

Consider the following expression (x-y+a)^2 + (x-z+b)^2 // Expand The result is ...
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### Extracting coefficients from a list of expressions

I have a list of the form, ...
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### how to get the set of coefficient of a trig function in terms of the sines and cosines of a given angle

Say I have an expression like this a Sin[\[Theta]]^4 + b Cos[\[Theta]]^4 + c Sin[\[Theta]]^3 Cos[\[Theta]] + d Sin[\[Theta]]^2 + e=0 My ultimate goal is to solve ...
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### Inversion in Fourier coefficients estimation problems

Let us suppose we have a coefficient vetor: coeff = {a0, a1, b1, a2, b2, ..., an, bn} with a total of (2*n + 1) elements. Those coefficients are applied in a ...
1 vote
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### Comparing two power series and extracting their coefficients

I have a standard mathematical problem that I was wondering how to solve efficiently by mathematica. Here is the problem. I have two power series expansions of a function ...
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### Replace coefficients with RootApproximant of themselves

I have an expression, not necessarily a polynomial, and want to take all the coefficients on whatever terms there are and replace them with the RootApproximant ...
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### Extracting the coefficient of a certain term from a polynomial

I want to take out the coefficient of z1^a1 z2^a2 ... zn^an from a polynomial function expr,where ...
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### How to get the coefficient list of their product from the coefficient list of two polynomials?

If I have the coefficient list of two polynomials ...
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### Calculating minimal unknown coefficients of a sum

I have a problem, where I have to find the minimum of a function with a sum in it (coefficients are unknown): psi[x_] := 1 + a*x + b*x^2 + c*x^3 + d*x^4 + ... ...
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### Can't use Coefficient properly

I could successfully solve an ODE (Ordinary Differential Equation) with this: ...
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### Extract system of linear equations from the linearly independent vectors

Dear StackExchange Community, I have a lot of linearly independent vectors, e[i]e[j], e[i]e[j]h[i], f[i]e[j], etc, and I have an equation for example ...
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Code: ...
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1 vote
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### Putting everything with the same power together

I'm doing some computations wich involves a lot of big polynomials, for example: ...
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### Simplifying the function for the common factors; and showing that it contains a multiplicative factor $i e^{i (6 x + 3 b + t)}$

I have the given long function for $\{x>0,b,t\}\in\mathbb{R}$ and $\{m,n\}\in\mathbb{N}$. I have two questions: This function contains many common factors in polynomial form (as can be seen in the ...
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### CoefficientList for unbounded list of variables

Consider a polynomial: expr = Sum[x[k] a[k] + x[k], {k, 0, K}]; I want to determine the coefficients for variables x[k] for each ...
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### How to ask Mathematica to extract all $y$-dependent terms in the given function $f(x,y,z)$?

I have a very large three-variable function $f(x,y,z)$ for real variables $\{x,y,z\}$ (I had to put only part of my original function because of the limit of $30000$ characters). Is it possible to ...
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1 vote
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### Is there any hope to compute the determinant of $56\times 56$ parametric matrix and simplify the result?

I have this $56\times 56$ parametric matrix $M$ and I want to compute its determinant where $\{t,y,z\}$ are some real parameters. I use Det[M] but it takes a lot ...
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### The list of coefficients of the "polynomial", which has the order of derivatives instead of degrees

I have some equation eqn = (A + B).x''[t] + Transpose[x'[t]].(2 A - 3 B + 1).x'[t] +(СС - 5).y'[t]+ Sin[x[t]+y[t]] I need to collect all the coefficients at ...
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