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Questions tagged [simplifying-expressions]

Questions on manipulating complicated expressions and making them look simpler using Simplify, FullSimplify and Reduce.

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Specifying properties of a function as assumptions

I am trying to simplify expressions involving a function $f: \mathbb C \to \mathbb C$ which satisfies $$f(-z) = -f(z), \quad f(z^*) = f(z)^*, \quad \forall z \in \mathbb C.$$ I do not want to specify ...
ummg's user avatar
  • 111
0 votes
1 answer
28 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
1 vote
0 answers
61 views

Simplification of expression with PolyLog[4,2]

I am trying to simplify the following expression. expr=1/2 \[Pi]^2 Log[2]^2-2/3 I \[Pi] Log[2]^3-4 PolyLog[4,2]+7/2 Log[2] Zeta[3] This ...
BabaYaga's user avatar
  • 1,888
1 vote
1 answer
77 views

Separation of variables

Is it possible to replicate the same procedure of placing the functions that depend on $r$ on one side of the equation and on the other side leave the equations that depend on $\theta$ in Mathematica? ...
Dayzk's user avatar
  • 147
2 votes
1 answer
80 views

A first order differential equation: Inconsistent solutions by two approaches

Assuming $a>0,b>0,c>0$, in matrix A = {{a - I*b, c}, {c, a + I*b}}; I am interested in solving the following differential equation $\frac{d}{dt}R(t) = -i(...
phy_std's user avatar
  • 143
6 votes
2 answers
185 views

Why is Mathematica not simplifying this matrix?

I have trouble simplifying the following matrix ...
phy_std's user avatar
  • 143
0 votes
0 answers
49 views

'KroneckerDelta' won't evaluate symbolically

I'm trying to get Mathematica to symbolically evaluate sums containing KroneckerDelta. It picks out the correct term when comparing the index agains a number, but ...
Fii's user avatar
  • 101
0 votes
1 answer
83 views

Simplification of arrays of a matrix

I want to simplify the arrays of a matrix, first I tried to define my constants then used "FullSimplify" but it does not work. Please see the screen shout. ...
Ali Bizhanpour's user avatar
1 vote
2 answers
58 views

Getting the recursive relation of series

If I have a finite sum of some terms which are the product of the prefactor, function f[i,j,k,a,b,c], and the x^m y^n z^k. I ...
liang zhang's user avatar
1 vote
0 answers
34 views

How to simplify the results of squared amplitude calculations in FeynCalc?

I want to calculate the squared amplitude of the Feynman diagram of double-pion photoproduction using FeynCalc package. Here is the code I created: ...
Albert Copperfield's user avatar
2 votes
1 answer
83 views

Expressing elliptic $\lambda^*(r)$ with radicals [closed]

For some small $r$, the values of $\lambda^*(r)$ can be expressed symbolically, see Elliptic Lambda Function equations $(11)-(34)$ Is it possible to get some of these expressions using Mathematica? I ...
Vaclav Kotesovec's user avatar
4 votes
1 answer
85 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
2 votes
1 answer
69 views

Compute curvature tensor constructed by a shifted connection

I'm using xAct package to compute the curvature tensor from a specific connection, of the form $\Gamma^a_{bc}= \mathring{\Gamma}^a_{bc} + S^a_{\:bc}$, where the first term is the Levi Civita ...
ayberk çakmak's user avatar
4 votes
1 answer
160 views

What's the reverse operation of TransferFunctionExpand?

Given a transfer funtion TransferFunctionModel[1/(s + I) + 1/(s - I) + 1/(s + 1) + 1/(s - 2)^2,s] we can obtain the polinomial form by using TransferFunctionExpand ...
metroidman's user avatar
3 votes
2 answers
329 views

Is there a way in Mathematica to simplify expressions based on inexact assumptions? [closed]

Is there a way in Mathematica to simplify expressions based on inexact or "relative" assumptions such as $x<<y$ or $x\approx y$? I see ...
Andrew Cheong's user avatar
0 votes
1 answer
45 views

How to simplify and expression subjected to constraints?

It is possible to simplify the following expression ...
Jee's user avatar
  • 386
2 votes
1 answer
43 views

Laplace Transform and Different Results [closed]

I have the following piecewise function and I take the Laplace Transform ...
Moo's user avatar
  • 3,334
0 votes
1 answer
35 views

Order of the output with simplification

How can I force mathematica to write the output of the following expression in the correct order? Also, how is to multiply the constant pre-factor by the terms inside the bracket? Input ...
SciJewel's user avatar
  • 422
0 votes
1 answer
44 views

Symbolic calculations with operator ordering

Given the following set of equations: ...
Jee's user avatar
  • 386
2 votes
1 answer
116 views

Is it possible to express $\text{Li}_2(-\frac18(-i+\sqrt{15})+\text{Li}_2(\frac18 (i+\sqrt{15})$ as an explicit real expression (not numeric)? [closed]

I obtain this expression in my calculations, and numerically I am sure that it is a real number. ...
MsMath's user avatar
  • 195
1 vote
1 answer
40 views

Issue with FullSimplify in StirlingS2 definition

I have previously asked a question about a problem simplifying an expression in Mathematica. The solution was to expand the definition of StirlingS2. This time, I ...
Cardstdani's user avatar
0 votes
1 answer
38 views

Problem calculating mean of probability distribution

I have a discrete probability distribution where $P(X=x)=(Factorial[n]/(n^x))*StirlingS2[x-1,n-1]$. So, when trying to calculate its mean with the following property: $\mu = \sum_{i} x_i \cdot P(x_i)$,...
Cardstdani's user avatar
0 votes
1 answer
76 views

FullSimplify not working as desired in Mathematica 11.3 [closed]

I have the following function in Mathematica: ...
SHASHANK RANJAN's user avatar
5 votes
2 answers
2k views

Why doesn't Mathematica simplify the expression under square root?

Give real x,y and z, I am trying to calculate the matrix ...
Jee's user avatar
  • 386
1 vote
2 answers
103 views

Simplifying expression efficiently

I have the following expression that I want to simplify to have an optimized/nice output. ...
BabaYaga's user avatar
  • 1,888
0 votes
0 answers
71 views

Verify simple equality involving integral

Can anyone kindly explain why Mathematica does not say that these two equations are the same? I have just removed two terms which multiply to one: ...
NC520's user avatar
  • 479
4 votes
2 answers
209 views

What to do when FullSimplify runs out of memory?

So close yet so far! I've read a number of posts here about tips and strategies for simplifying expressions. I hope this case still offers guidance to others. I have an expression that (just!) fits ...
RealDisinformation's user avatar
1 vote
0 answers
43 views

Issue about simplify dirac delta function [duplicate]

When I trying to simplify a dirac delta equation, I got the following result. The result confused me. How can I make the second equation output true ...
Lichun Chang's user avatar
5 votes
1 answer
281 views

Mathematica failing to evaluate sum

I have some sums to simplify/evaluate, but for some reason I can't even get Mathematica to simplify relatively simple sums. For example, I tried to get Mathematica to simplify this sum: $$\sum_{k=0}^{...
Oliver's user avatar
  • 51
2 votes
3 answers
148 views

Finding $\frac{\cos(b)}{\cos(a)}$ given $\cos(x) e^{i y} = \frac{\sin(a)}{\sin(a+b)}$ and $-i \sin(x) e^{i y} = \frac{\sin(b)}{\sin(a+b)}$

I have real $x$ and $y$, and I have the following implicit definitions of (complex) $a$ and $b$: $$\cos(x) e^{i y} = \frac{\sin(a)}{\sin(a+b)}$$ $$-i \sin(x) e^{i y} = \frac{\sin(b)}{\sin(a+b)}$$ I ...
user196574's user avatar
2 votes
2 answers
55 views

Difference between variables and expressions for ReplaceAll

I'm doing some GR calculations with xAct. I get an expression that is heavy. In order to simplify the results, I try to use the function ReplaceAll in simple cases. ...
TrodaroX's user avatar
2 votes
0 answers
108 views

Is there a way to force 'Simplify' to use some assumptions?

First time poster. I have a basic question about 'Simplify'. I am encountering a problem when trying to simplify some algebraic expressions, where I find an unexpected behaviour of the 'Simplify' ...
Johnny Lemmon's user avatar
2 votes
3 answers
486 views

Why is Mathematica not simplifying eigenvalues?

For matrix A = {{x*Exp[I*y], z}, {z, x*Exp[(-I)*y]}}; , Mathematica yields the following eigenvalues: ...
Jee's user avatar
  • 386
3 votes
4 answers
170 views

Sort Column as a Row

I have a = {1, 2, 3, 10}; b= {2, 3, 4, 8}; t= Do[If[a[[i]]+b[[i]]>3,Print[a[[i]]],"No"],{i,1,4}]; 2 3 10 I need to get the result; t={2,3,10}
Alyasaa Jasim's user avatar
5 votes
1 answer
281 views

Mathematica stuck for more than 12 hours on getting numerical value

The following expression when summed from $k=0$ to $\infty$ converges but returns an absolutely hideous expression that I cannot fit in here due to the character limit. I want the numerical value up ...
QFTheorist's user avatar
1 vote
0 answers
34 views

Separate exponentials [duplicate]

Good afternoon, I have an expression Exp[2 I (t - tau) + a] + 2 Exp[2 I t + b] + 3 Exp[-I t + b] And I want to write it as a summation of powers of Exp[I t]. So, <...
Bou's user avatar
  • 11
3 votes
1 answer
106 views

`FullSimplify` is failing to combine terms with `DiracDelta` functions

DiracDelta[x] + Pi DiracDelta[x] == (1 + Pi) DiracDelta[x] is obviously true by inspection. And yet, ...
tparker's user avatar
  • 1,856
0 votes
0 answers
33 views

How to simplify the conditions of a Piecewise function (Maximize output)?

I'm new on the forum and on Mathematica. I'm studying the crest of a function of the three variables c, e, g3. With "crest" I mean I'm maximizing the function only over c, keeping the ...
VitoV's user avatar
  • 1
0 votes
0 answers
53 views

Speeding up the output of DSolveChangeVariables

I am trying to change the variable in a differential equation using the above mentioned function. This is what I did: ...
RKN's user avatar
  • 1
1 vote
1 answer
62 views

Finding constant term in product expression

I've an expression which is product of 20 or more factors of polynomial, something like $$\left(1-\frac{pq}{z^i}\right)(1+pq z^j+z^k)$$ and I want to find coefficient of $z^0$. SeriesCoefficient works ...
xandar's user avatar
  • 13
0 votes
1 answer
63 views

Simplifying powers of 10 in expression with square root [duplicate]

FullSimplify doesn't do anything with the following expression, while it is easy to simplify it by hand. ...
L. P.'s user avatar
  • 101
0 votes
0 answers
43 views

Puzzling behavior of `Assumptions` in `Solve`

With Wolfram Language 13.3.0 Engine when solving the following equation: ...
Jos Bergervoet's user avatar
5 votes
2 answers
107 views

Simplification to avoid 1/0

Is there a way I can get Mathematica to simplify the following equation so I can avoid $1/0$ errors later? The command I used is: ...
L. P.'s user avatar
  • 101
1 vote
1 answer
80 views

Simplification of trigonometric expressions

I would like to automate the simplification of certain trigonometric expressions, such as ...
Sheparcapea's user avatar
5 votes
2 answers
127 views

Simplifying a logical expression with multivariate polynomials

I have several expressions similar to a (a b + c d) != 0 || b (a b + c d) != 0 || c (a b + c d) != 0 || d (a b + c d) != 0 and I would like to reduce them ...
მამუკა ჯიბლაძე's user avatar
2 votes
1 answer
176 views

How can I get stronger simplification than FullSimplify?

Short description: Is there a simplification that can for a>1 simplify ...
Jos Bergervoet's user avatar
8 votes
3 answers
489 views

How to "factor out" units?

I have a huge expression that makes use of Mathematica's units support (Quantity[]) that I know evaluates to a dimensionless quantity. However, I'm unable to get <...
小太郎's user avatar
  • 213
4 votes
2 answers
199 views

Putting a term under the square root

I want to put a term under the square root (but with Mathematica), such that $$(1+t)^2\sqrt{1+\frac{t^3}{(1+t)^3}}$$ is transformed to $$\sqrt{(1+t)^4+(1+t)t^3}.$$ I've tried all the forms of ...
lesobrod's user avatar
  • 1,699
0 votes
1 answer
57 views

Manipulating an expression into the form I want

I have an expression arising from a physics problem:(c Sqrt[-me^2 + mr^2])/mr, where c, me, ...
Sang Dhong's user avatar
1 vote
1 answer
84 views

How to group terms of a Fourier series properly?

I want to organize my expressions as a fourier series of sin and cos. That is, I want them to be of the form $$a_0 + a_1 \cos[ w t] + b_1 \sin[ w t] + a_2 \cos[2 w t] + b_2 \sin[2 w t] + ... $$ ...
ions me's user avatar
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