Questions tagged [simplifying-expressions]
Questions on manipulating complicated expressions and making them look simpler using Simplify, FullSimplify and Reduce.
1,692
questions
2
votes
0answers
27 views
Compare 2 expressions with variables
I want to check if two expressions are equivalent with Mathematica. For example, is $2 x + 4 + 2$ equivalent to $2 (x + 2 + 1)$.
I tried the === operator, which I ...
1
vote
1answer
44 views
Exploit bilinearity of KroneckerProduct symbolic calculations and inconsistence (apparently)
Mathematica 10 recognizes the bilinearity of the trace and the Kronecker product, as well as Tr$\otimes$Tr$(A\otimes B)=$Tr($A$)Tr($B$). But I have issues trying to implement this in symbolic ...
1
vote
1answer
24 views
Simplify Difference of Conjugate Pairs
Is it possible to easily simplify the difference of conjugate pairs?
In particular, if there's just a single variable, then
FullSimplify[a - Conjugate[a]]
...
0
votes
1answer
40 views
Simplify Jacobi Polynomials
How can I force Mathematica to use the identities satisfied by Jacobi polynomials
$$
(1-\cdot)P_n^{(\alpha+1,\beta)} = \frac{2}{2n+\alpha+\beta+2}\left((n+\alpha+1)P_n^{(\alpha,\beta)}-(n+1)P_{n+1}^{(\...
7
votes
1answer
391 views
Why does Mathematica give exact solution 0 for this indeterminate expression?
I have this function:
$\frac{(1-\cos (\theta )) \sin (n x)}{\pi (-1)^{n+1} \cos (\theta )-\cos (\theta ) \cos (n x)+2 \pi \cos (n x)+\cos (n x)+\pi (-1)^{n+1}},$
and I want to know its value for $...
2
votes
3answers
111 views
Turning numbers embedded in deeply nested lists into strings [closed]
This must have a simple answer, but I cannot think of it. I want to take the numbers in a list such as:
{1,{2,{{3,4},{5,6}},7,8}
into strings. ToString will turn the whole list into a string. ...
0
votes
2answers
30 views
How do you simplify a boolean expression (!A B)+(B !C)+(BC)+(A !B !C)? [closed]
How would you simplify the following boolean expression (!A B)+(B !C)+(BC)+(A !B !C)?
I factorised B and managed to get B(!A+!C+C)+(A !B !C) = B+(A !B !C), but I do not know where I should go next.
...
2
votes
3answers
82 views
Finding the value of an expression [closed]
Here is an expression that can be easily shown to equate 2 by analysis.
$$\sqrt[3]{7+\sqrt{50}}+\sqrt[3]{7-\sqrt{50}}$$
But no matter what i try Mathematica always shows a complex result:2.62132 + 0....
3
votes
1answer
76 views
Is there a way to force Mathematica to collect terms in a more readable way?
I've got the following result from an operation in Mathematica:
...
4
votes
1answer
56 views
How do I extract just a part of an expression?
I have the result of an operation:
((t0M^2 + t1M^2)*xC/(2*t0M^2)
What is the best way to get just the $\frac{t0^2+t1^2}{2\space t0^2}$ from this expression? This ...
-1
votes
1answer
43 views
Simplifying complex expresion (without ComplexExpand or User defined rules) [closed]
Many times, I've struggled with simplifying complex expressions, such as this extraordinarily simple expression, and Mathematica wont do it:
...
0
votes
0answers
49 views
How do I define if two variables are equal to each other
Let's say I have the function x + y = z and I know that x = y. How can I define this in Mathematica?
I tried using
...
4
votes
1answer
86 views
A pattern replacement to force Mathematica to replace inexact 0 multiplication by zero
Hi Consider the following expression which contains multiplication by inexact 0
...
1
vote
0answers
63 views
Why doesn't Mathematica simplify? [closed]
Consider the following:
Simplify[Integrate[x^(a), {x, x1, x2}], x1 > 0 && x2 > 0 && a > 0]
Mathematica doesn't simplify this for me. I ...
0
votes
0answers
53 views
How to deal with complex equations in Solve method?
I am trying to deal with complex equations to solve them and use them in the plot. I want to know why these equations are not being solved.
...
1
vote
1answer
42 views
Is there any way to prioritize Gamma function?
In Mathematica, if you type
Gamma[1, 0, -a]
It automatically simplifies to 1 - E^a. I wonder though if there is a way to stop ...
4
votes
0answers
41 views
Force Solve to respect unit system
I give Solve quantities in FPS and it returns resulting quantities in SI, necessitating that I add an entire section to my workflow where I pick apart the solution ...
3
votes
1answer
104 views
Simplifying algebraically
Is there a way to derive an simplified expression from other equations. Or create an alternate form such that the main equation takes other equations and manipulates the main function.
Here is what I ...
2
votes
0answers
25 views
Computations with OptimizedExpressions without completely expanding them
I have to manipulate huge expressions that are rational functions of many (ā¼30) variables with integer coefficients. Storing them just as a ratio of two polynomials would be impractical. But they can ...
1
vote
0answers
33 views
Group parameters that only occur together [duplicate]
I have a long and complex univariate expression with many parameters, $ f(x; a, b, c, d, ...) $.
I would like to group those parameters which only ever occur together.
Here is a very simple example ...
1
vote
1answer
27 views
Simplify expression with abstract matrices
After defining a commutator function
Commutator[X_, Y_] := X.Y - Y.X;
I would like to be able to simplify abstract matrix algebra expressions such as
...
4
votes
1answer
59 views
How to Force the PolyGamma[0, x] function or the HarmonicNumber[ x ] function
I'm crunching some infinite summations, and sometimes Mathematica generates results that have the PolyGamma[0, x] function (which is the Digamma) and sometimes the <...
1
vote
1answer
38 views
Simplify terms with delayed and immediate function definitions
Say I want to define a function fwith input x but also involving parameter p not yet ...
2
votes
0answers
74 views
Why aren't radians dimensionless?
Ī± = Quantity[-3, ("Radians")/("Seconds")^2];
Ļ = Quantity[-4, ("Radians")/("Seconds")];
r = Quantity[2, "Feet"];
at = Ī± r
an = Ļ^2 r
a = Sqrt[an^2 + at^2]
...
1
vote
0answers
54 views
Simplification of expression with sum of absolute values
I try to simplify following expression
1/2*(Abs[a1] + Abs[b1] + Abs[c1] + Abs[d1]),
where a1, b1, c1, d1 are quite long:
...
1
vote
1answer
37 views
Mathematica reduces domain when simplifying function
This question was initially (wrongfully) posted on Mathematics SE.
I have the following expression:
$$
\sqrt{1 + 10^{\frac{rdb}{10}} + 2^{1 + \frac{rdb}{20}} 5^{\frac{rdb}{20}} \cos(\mathrm{pdiff})}
...
1
vote
1answer
84 views
How to calculate unknown function in a equation analyticaly? [closed]
I want value of u1 in terms of T1. How i will be abel to do this?
...
1
vote
1answer
43 views
Reverse substitution [duplicate]
If you apply rules and then simplify you may get something like.
(25 A^2 hbar Sqrt[Ļ])/Sqrt[hbar m w]
How would you get mathematica to rewrite this in terms of E ...
2
votes
1answer
37 views
Why does ReplaceRepeated work differently in numerator and denominator?
I'm confused about the behavior of ReplaceRepeated.
ReplaceRepeated[a Sqrt[b], Sqrt[b] -> c] gives the expected (* a c *), ...
1
vote
1answer
70 views
Pochhammer Simplification
Assumption:: m and n are integers and greater than zero.
$Assumptions = {Element[m, Integers] && m >= 0, Element[n, Integers] && n >= 0}
...
4
votes
4answers
320 views
0
votes
0answers
19 views
Running out of memory when expanding an symbolic expression using rules.How to handle such cases?
while deriving equations related to dynamics of 6 connected body, I ended up creating about 3000 set of rules,because of which final expression looks simple, now the issue is when i want to ...
0
votes
0answers
37 views
Assumptions behavior in Refine[Sin[n Pi/2]] [duplicate]
I don't understand why this first expression returns a correct result:
In> Refine[Sin[n Pi/2], Element[n, Integers] && Mod[n, 2] == 1]
...
0
votes
1answer
38 views
Why does restricting the domain not eliminate this solution?
Beside this specific problem I'm wondering if there's a more explicit way that I can understand when Solve and Reduce will find solutions. I find myself repeatedly getting stuck where I'll get ...
0
votes
1answer
65 views
How to verify an inequality?
I'm working with an expression that seems to be non-positive, but I'm having a hard time verifying it:
...
0
votes
2answers
39 views
Assuming a root and simplify
I want to simplify an expression assuming a given value is a root. Say s[v] is a root of f[x,u]-f[x,v]. Sometimes Assuming works, for example,
...
1
vote
0answers
55 views
Help with double pendulum equations
I'm 16 and I'm pretty new to Mathematica. I've been working on a personal coding project which has some funky maths in it and I am kinda struggling. I've solved for the 4 polynomials but they answers ...
4
votes
6answers
330 views
Simplify or rules don't work with square roots
I am trying to simplify a complicated expression and neither Simplify nor rules are working for me.
Here is a very basic example of what I am trying to do:
...
2
votes
3answers
74 views
Why Mathematica doesn't simplify this multiplication?$c^{-L} (c r){^L}$ [closed]
Why Mathematica doesn't simplify this multiplication? I don't know Mathematica it can or not? Please accept my ignorance :)
c^-L (c r)^L
0
votes
1answer
25 views
Reducing and finding the magnitude of complex functions
I am very new to Mathematica and I've been trying to use it to perform calculations with complex numbers. I am mainly trying to find the norm of complex expressions with an unknown variable. For ...
0
votes
1answer
39 views
Exponential function not simplified by FullSimplify?
I'm trying to understand why the first expression doesn't simplify while the second does:
...
1
vote
0answers
40 views
Are two equations equal
I have a two vector laplacians which have very long equations and I have to verify that they are equal, and doing that by hand would take an hour, I have tried using LHS == RHS, which should print ...
1
vote
3answers
39 views
Simplify Trigonometric Expressions so that they no longer contain specific Trigonometric Ratios [duplicate]
I want to simplify the following Trigonometric expression so that it no longer contains Tan[a] and Cot[a]. How can I do that?
<...
1
vote
2answers
73 views
Collect for nonlinear terms
Is there a way to expand Collect, so that it does not only separate equations by polynomial order, but by general nonlinear functions?
For example
...
0
votes
0answers
38 views
Simplification of symbolic vector and matrices representation
I'm new to the Wolfram Language programming and I cannot manage to do the following.
I wish to use Wolfram Cloud to simpilfy a heavy vector and matrix expression using symbolic complex vectors (...
1
vote
0answers
53 views
Simplify sufficient to check for infinity?
I have a function, comprising of many functions in its definition, which is being simplified to ComplexInfinity. My goal right now is to check each of the comprising function for infinity.
If I run <...
0
votes
2answers
54 views
Reducing expressions to simpler form using a known equality
I generally have a lot of trouble getting Mathematica to produce readable versions of solutions.
For example, today, when solving a symbolic system of homogenous ODEs (with boundaries provided as ...
0
votes
0answers
36 views
Gamma and Pochhammer simplification
I want to perform some simplification on Gamma function and Pochhammer symbols. For example,
...
2
votes
0answers
39 views
Why FullSimplify doesn't work when subscript included?
This is OK.
FullSimplify[l[t] + r[t], {m[t] == l[t] + r[t]}]
But when I add a subscript to l, FullSimplify can not return the correct result. Is this a bug?
I will be grateful if anyone can give me ...
4
votes
2answers
68 views
LaplaceTransfrom with time shifting
Hi I'm wondering if there's some workaround to get Mathematica to use time-shifting identities for Laplace and Inverse Laplace transforms. My examples are below.
...
