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Questions tagged [coefficients]

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Getting coefficients list of a series expansion at a point different from 0

I would like to get the coefficients of a series expansion at a point different from 0. Example: Series[Cos[Pi*x], {x,1,6}] which gives $-1+\frac{1}{2} \pi ^2 (x-...
edrezen's user avatar
  • 113
1 vote
1 answer
68 views

How can I extract the constant coefficient in polynomial?

I have an equation with this form: eq1 = 0.38*u1[t] + 0.285*u1[t]*v1[t] + 0.85*u1[t]^2. I want to extract the coefficient of ...
saboor savvafi's user avatar
1 vote
2 answers
97 views

Differential behaviour of FreeQ function depending on the number of terms in a sum

I have an expression consisting of a sum of terms. It looks like this in simplified form: $-\frac{e^{-t/t_1} \,a \, b \, c}{d} \, U_1 - \frac{e^{-t/t_2} \,a \, e \, c}{d} \, U_2 -\frac{e^{-t/t_2} \,a \...
CountBackwardsFromInfinity's user avatar
0 votes
1 answer
31 views

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 ...
GBaardink's user avatar
4 votes
1 answer
89 views

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 ...
user1620696's user avatar
0 votes
1 answer
42 views

Extracting coefficients from a list of expressions

I have a list of the form, ...
Patrick.B's user avatar
  • 1,511
0 votes
0 answers
56 views

Numeric coefficients of a series/polynomial

In my work, i usually come across expressions of the form: $$\text{L3}=\frac{625 f_5^{30} q^4}{f_1^{31}}+\frac{24458 f_5^{24} q^3}{f_1^{25}}+\frac{25436 f_5^{18} q^2}{f_1^{19}}+\frac{25415 f_5^{12} q}{...
Sangama's user avatar
  • 23
1 vote
0 answers
48 views

Problem with using RuleDelayed (:>) [closed]

I have defined a rule using rule delayed function as follows: innerWithDxU = (f1_ D[f2_[x,y],x]f3_[x,y] :>-f2 [x,y]D[f1 f3[x,y],x] ); ...
Rumayel Hassan Pallock's user avatar
3 votes
0 answers
42 views

Cannot add a constant coefficient to LineIntegrate

I'm quite confused on how you're supposed to use constant coefficients in Mathematica integrals. The upvoted and accepted answer on Mathematics stackexchange (https://math.stackexchange.com/a/48021/...
Cedric Martens's user avatar
0 votes
2 answers
60 views

Creating function with array input with desired coefficient and evaluate it

I had asked the same question before here Creating a list of functions with desired coefficients but did not get the desired answer, may be I was not clear in my question. I have defined this function ...
Learner's user avatar
  • 219
1 vote
2 answers
63 views

Neglecting coefficients of a given list

Suppose I have some complicated expressions, I want to extract some terms with $\{a_1, \cdots, a_n\}$ out of the complicated expressions without considering coefficients. For example, here is my trial....
phy_math's user avatar
  • 923
2 votes
1 answer
93 views

Creating a list of functions with desired coefficients

I have defined this function to results some list of functions, however its not returning what I want ...
Learner's user avatar
  • 219
9 votes
9 answers
761 views

How to extract coefficients and powers from expressions with non integer powers?

I want to extract coefficients and powers of the expression $$3-2x+7x^{2.1}+x^{2.4}-5x^3$$ Code: expr = 3 - 2 x + 7 x^2.1 + x^2.4 - 5 x^3; To get a result such as:...
Mohamed Mostafa's user avatar
0 votes
0 answers
28 views

How can I find the coefficient of some function of varying inputs in a list? [duplicate]

I have a list klist={4 K[{1}, {1}], K[{2}, {2}], (2 K[{2}, {1, 1}])/("Ndim")} where K[{list_1}, {list_2}] is some ...
00123456's user avatar
2 votes
1 answer
118 views

How can I find coefficients of quadratic and cubic terms?

I have this code: ...
justJasper's user avatar
1 vote
0 answers
25 views

Finding the coefficients of a decomposition of complicated expression into products of special functions

I have the following expression which arises while studying minimal models in CFT. The 4-point amplitude of scalars is given by $$G(z,\overline{z}) = ((1-z)(1-\overline{z}))^{\frac{m-1}{m+1}}\mathcal{...
QFTheorist's user avatar
0 votes
0 answers
48 views

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 ...
larry's user avatar
  • 735
0 votes
1 answer
37 views

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 ...
Cairo Martins's user avatar
1 vote
1 answer
92 views

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 ...
Physics Moron's user avatar
2 votes
1 answer
49 views

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 ...
D. Brown's user avatar
  • 304
0 votes
1 answer
146 views

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 ...
liang zhang's user avatar
2 votes
2 answers
111 views

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 ...
lapcal's user avatar
  • 531
0 votes
0 answers
42 views

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 + ... ...
Hrvoje Krizic's user avatar
0 votes
1 answer
62 views

Can't use Coefficient properly

I could successfully solve an ODE (Ordinary Differential Equation) with this: ...
taratana's user avatar
5 votes
1 answer
97 views

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 ...
IvaMat's user avatar
  • 53
4 votes
1 answer
142 views

Why does Solve return an empty list?

Code: ...
Student's user avatar
  • 177
1 vote
0 answers
73 views

Putting everything with the same power together

I'm doing some computations wich involves a lot of big polynomials, for example: ...
User0212's user avatar
0 votes
0 answers
86 views

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 ...
math2021's user avatar
  • 749
2 votes
0 answers
55 views

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 ...
Belfaunder's user avatar
0 votes
0 answers
51 views

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 ...
charmin's user avatar
  • 1,159
1 vote
0 answers
72 views

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 ...
charmin's user avatar
  • 1,159
0 votes
0 answers
63 views

Finding the coefficients that equate two sides of an equation

I have the following equation : $f(x)p(x)=g(x)p(\frac{x}{q}) + g(\frac{1}{xq})p(xq)$ q is a constant and $f(x)$ is a polynomial whose expression I have. Similarly $g(x)$ is also a known function. $p(x)...
Ceethemez's user avatar
4 votes
2 answers
93 views

Normalizing the output of Apart

My question is closely related to this one but the accepted answer does not meet my needs. I have a rational function $f(x)$ in one variable which admits a partial fraction decomposition of the form $$...
Start wearing purple's user avatar
1 vote
1 answer
123 views

Problem in getting coefficients list of power series solution of y''[x]*y'[InverseFunction[y][x]] - y'[x] == 0?

I have tried to get solution of the following ODE: y''[x]*y'[InverseFunction[y][x]] - y'[x] == 0 Using the code given below, the solution is a formal power series ...
zeraoulia rafik's user avatar
4 votes
2 answers
325 views

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 ...
Thrash's user avatar
  • 405
1 vote
0 answers
480 views

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 ...
Eduardo's user avatar
  • 13
3 votes
3 answers
112 views

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, "$x_k$", ...
gen's user avatar
  • 195
6 votes
3 answers
432 views

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.
dantopa's user avatar
  • 1,080
1 vote
2 answers
211 views

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,...
newtothis's user avatar
11 votes
2 answers
681 views

Out of memory when computing a coefficient of a large symmetric polynomial

...
PalmTopTigerMO's user avatar
2 votes
1 answer
99 views

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 Internal`FromCoefficientList, and finally replacing the value of the free parameter with a ...
Utsab Dey's user avatar
0 votes
1 answer
88 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 ...
Teo7's user avatar
  • 139
0 votes
1 answer
209 views

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 ...
Lorenzo Bagnasacco's user avatar
1 vote
1 answer
214 views

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 ...
Elie's user avatar
  • 11
1 vote
0 answers
80 views

Coefficient works on $\pi$, $x$ and $x^2$, but not on $\pi ^2$

Consider (\[Pi] + 2 \[Pi]^2 + 3 x + 4 x^2) Executing ...
ThunderBiggi's user avatar
  • 1,195
1 vote
2 answers
122 views

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, ...
akozi's user avatar
  • 873
0 votes
1 answer
247 views

Collecting coefficients of non-commutative products from an expression

I am trying to manipulate a Hamiltonian with non-commutative operators, $a_j,a_j^\dagger$. After some algebra using NCAlgebra package in Mathematica, I have an expression like, $$H = C_1 (b**a) + C_2 (...
SlothForeva's user avatar
2 votes
1 answer
474 views

How to expand a function as a linear combination of other functions?

I would like to be able to expand certain functions as linear combinations of other specified functions when I know that the original function can be represented in such a way e.g. we know that $\sin^{...
Chris's user avatar
  • 1,043
0 votes
1 answer
173 views

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 ...
dtn's user avatar
  • 2,404
0 votes
2 answers
84 views

Kernel dies when trying to compute coefficients in a linear sum involving expressions like b[1,2][3,4]

The following happens on 11.0.1.0: Have ...
მამუკა ჯიბლაძე's user avatar