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

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11
votes
2answers
211 views

Is mathematica's right click menu customizable to add Simplify tools?

Mathematica provide Algebraic Manipulate palette for simplifying expression. But the palette window will always stay on top, which is quite annoying. Is is ...
1
vote
1answer
79 views

Simplify fractions and square roots

I would like to 'Simplify' Sqrt[5/6]/2 to Sqrt[5/24] I've tried to penalize Times and Rational using ComplexityFunction, ...
3
votes
3answers
104 views

Simplification behaviour of subscript expression: is this correct?

Why does the code (Mathematica version 10.0.2.0, Linux x86-64): Subscript[Subscript[S,i],j] Subscript[Subscript[S,i],j] // Simplify output the expression: ...
0
votes
0answers
83 views

How to simplify a messy integrand by integrating by parts

I have a function x[t] and a messy integral over t, containing x[t], ...
1
vote
0answers
51 views

Eliminate a variable from a differential equation and an algebra equation then collect the remaining variables

Recently, I am attempting to eliminate a variable from a differential equation (DE) and an algebra equation (AE), then collect the remaining variables as a new (grand) parameter. Actually, I have ...
1
vote
2answers
66 views

Translating syntax of a pure function

I have a matrix in complex exponential form. I want to factor out the complex exponential form and then express the inside in the a+i*b form. For example: \begin{bmatrix} e^{i \frac{\pi}{4}} ...
1
vote
0answers
49 views

Write trigs in terms of Cosine only

I have a long expression having terms that go in squares like Sin[x]^2 and Sin[x/2]^2 and so on... I would like to rewrite my ...
0
votes
1answer
89 views

How to impose Assumptions for a list of variables?

I've got an $Assumptions variable that I'd like to apply to my whole notebook, looking like so at the moment: ...
0
votes
3answers
129 views

Manipulation linear systems of equations

I have the following system of equations: i1 = ix - β*ib; i2 = (β + 1)*ib; i3 = ix + ib; vx = i1*Rc + i3*Rb; v1 = i2*Rϵ + i3*Rb; v1 = -ib*rπ; I tried using: ...
0
votes
1answer
47 views

inverting PowerExpand

Since I couldn't respond to the question "Can you give a situation in which you would want to do this?", I will post this situation as a new question. I am plotting a complicated expression with a ...
6
votes
1answer
116 views

What is the reason that $zz^*$ is not written as $ |z|^2$ sometimes?

For a general (complex) number $z$ I sometimes get terms that explicitly writes (for instance) $$2zz^*+|z|^2. $$ I should add that these expressions come from long calculations involving packages ...
3
votes
2answers
120 views

Show Factorial instead of Gamma in the result of RSolve

Now I wanted to solve for a recurring function with RSolve. Here's how I tried: ...
2
votes
1answer
69 views

How to make Simplify (and FullSimplify) give a default output if $Assumptions are contradictory

I have a function (deep inside my package) that looks like ...
3
votes
3answers
220 views

How can I make Mathematica trigger the simplification of ArcCos[a]+ArcCos[b]?

According to this Wikipedia subsection my guess is that I should be able to convince Mathematica to return zero when doing ...
3
votes
1answer
141 views

FullSimplify does not distribute Abs over multiplication

FullSimplify[Abs[x]^2, x \[Element] Reals] reasonably returns x^2, but the barely-more-complicated expression ...
1
vote
3answers
73 views

Simplfying with Log and Exp functions

Short question, I have: $ \log \left(0.617424 e^{-1.19761 (W-0.427026)^2}\right)-\log \left(0.617424 e^{-1.19761 (0.116019\, -W)^2}\right) $ W is real and ...
0
votes
1answer
67 views

Difficulties in algebraic simplifications

I am a new user, and I am a bit puzzled while experimenting with Mathematica functions, their derivatives and derivatives of functions. I have an expression such as: ...
0
votes
1answer
62 views

I have a term 'Keff' in terms of 'W'. I need to write 'W' in terms of 'Keff'. Does Mathematica provide an option for that

I have read similar answers on this topic. I am still not able to execute my code.The code is as follows. ...
0
votes
1answer
133 views

Getting mathematica to factor out constants and apply euler's identity to a table

I'm doing some quantum mechanics homework that I'm going to eventually generalize to higher spin states, so the solutions are going to need to be decently independent of the dimensions of the table ...
0
votes
1answer
49 views

How can I prevent exponents from appearing in an expression?

I've found posts dealing with showing/hiding exponents for numbers, like in scientific notation. But what if I have a general expression? I have an expression like this, ...
1
vote
1answer
59 views

Simplify the following transformed equation [closed]

y=7f(-1/6(x-1))+1 The base function is f(x)=x^2. I just don't understand where the ^2 went and how to simplify this. Any help is much appreciated, thanks.
1
vote
0answers
36 views

Factoring rationals from equation based on digit complexity?

Consider an equation of the following type: ( poly = (3 x)/35 + (6 y)/7 ) == 0 If we apply the command Factor to this ...
1
vote
1answer
103 views

Simplify not working for a real part of a complex expression [closed]

When I try to get the real part of a term, for example: $\qquad \Re\left(\frac{e^{-i k} \left(2 k^2+\pi ^2 \left(-1+e^{i k}\right)\right)}{\pi ^2-k^2}\right)$ Mathematica will output the same thing ...
1
vote
1answer
79 views

Extract coefficients from trigonometric polynomial [closed]

Suppose I have: f[r_, ϕ_] = C1 Cos[ϕ]r + C3 Sin[3 ϕ] r + C4 Sin[4 ϕ] r^4; How do I extract the coefficient of a chosen trigonometric term, let's say ...
4
votes
1answer
48 views

Reliable testing of identities (example: modular functions)

Take, for illustration, the following function (bonus points for anyone who identifies where it comes from!), defined on the upper half plane: ...
0
votes
0answers
61 views

How to combine similar terms in a density matrix expression? [Ref: Quantum Computing]

I tried the following : Simplify, FullSimplify, and Expand. Due to this problem, I am not ...
1
vote
0answers
53 views

Running out of memory when doing non-commutative arithmetic

I need to calculate particular coefficients of the composition of two power series in non-commutative variables. The code below which works fine truncates power series in degree $n=5$. For $n=6$ (the ...
1
vote
1answer
173 views

Dealing with indicator functions

I am calculating the integral of two indicator functions with Mathematica. I'm having difficulty in imposing assumptions. What I have done so far: To define an indicator function: ...
11
votes
0answers
79 views

FullSimplify does freaky things with approximate Gaussians [duplicate]

I was playing around with Vitaliy Kaurov's neat answer to this question, and found something a bit unusual: ...
1
vote
0answers
64 views

DiracDelta of a function

If I have, for instance, FunctionExpand[DiracDelta[x^2+x-3]] it evaluates to ...
2
votes
3answers
74 views

Series: two varibles, how to eliminate the (product) higher order

I have a function of $f(x,y)$, where $x,y$ are very small numbers. I want to series expand it to the $3$rd power. However I don't want the terms such that $x^2y^2$, $xy^3$ etc. because I would reckon ...
1
vote
0answers
91 views
1
vote
0answers
39 views

Reduce excess Log[] [closed]

I am trying to solve a differential equation using DSolve: DSolve[y'[t] == t^10 eps^-y[t], y[t], t] And get the following output: ...
3
votes
1answer
169 views

Separate variables in equation

I need to know is there a way to separate the desired variables in the equation at one side of the equality. For instance, the following equation ...
1
vote
1answer
50 views

Need help simplifying final expression [closed]

I was carrying out a function and ended up with the desired answer, but for some reason, Mathematica keeps giving me the answer in a strange numerical form. ...
2
votes
1answer
80 views

How to replace $-x^{}\,y^*-y^{}\,x^*$ by $-(x^{}\,y^*+y^{}\,x^*)$?

Up to now, I have tried some codes like the following: ...
2
votes
0answers
55 views

Simplifying symbolic expressions using TensorExpand

Following my previous question I have this issue using TensorExpand: KroneckerProduct[x, y].(KroneckerProduct[2 z, w]) // TensorExpand results in ...
0
votes
1answer
72 views

How to write an expression in the desired form?

I have the following code: ...
3
votes
0answers
121 views

Is it possible to simplify an expression in vector form, which involves crossproduct and dot product?

I often need to simplify expressions involving cross product and dot product, for example: f = Dot[Cross[Cross[p1 - p, e1], Cross[p2 - p, e2]], Cross[p3 - p, e3]] ...
3
votes
2answers
124 views

Simplification of products of KroneckerDelta[]

What is the reason why the following expression does not simplify to True? ...
9
votes
1answer
82 views

Problem with simplification KroneckerDelta

Bug introduced in 8.0 or earlier and fixed in 9.0 I have: ...
3
votes
1answer
81 views

Simplifying an expression with complex variables

The other day I was trying to simplify the following expression of $w \in \mathbb{C}$ and $|w| < 1$: $$f(w) = \left|\frac{2}{(\frac{w+1}{1-w}+1)^2}\right|^{-\Delta} \cdot \frac{1}{\left|{\rm ...
4
votes
1answer
91 views

FullSimplify on complex numbers seems inconsistent

FullSimplify[c Conjugate[c]] returns Abs[c]^2 while FullSimplify[2 c Conjugate[c]] ...
5
votes
1answer
87 views

Simplify with a condition

I have an expression, $-a (u + a v)$, and I would like to simplify it using the fact that $a^2 = 1$. I have tried Simplify[Expand[-a (u + a v)], a^2 == 1] but ...
8
votes
1answer
103 views

evaluation of the sum of KroneckerDelta

I need help. I need to know why the next code doesn't simplify in Mathematica 10 but it does in Mathematica 8. I need some similar in version 10. What can I do? ...
2
votes
1answer
76 views

FullSimplify gives wrong answer when operating on HypergeometricPFQ

When I try to simplify this hypergeometric function FullSimplify[HypergeometricPFQ[{1/2 - n/2}, {-(1/2) - n/2}, -a^2]] Mathematica 10.0.1.0 returns ...
1
vote
1answer
39 views

Why doesn't Simplify use my own TransformationFunction?

I define a simple TransformationFunctions via: tfTest[e_] := e /. {x^2 -> Hold[x*x]} and try to use it with ...
2
votes
1answer
105 views
5
votes
0answers
52 views

External and internal Assumptions on `PiecewiseExpand` and `Mod`

After this question I'm intrigued about the different behaviors depending where and how the assumptions are given. ...
1
vote
1answer
45 views

Simplify Mod to subtraction when possible

FullSimplify[Mod[t,10], t>101 && t<109] It's a long shot, but can I get Mathematica to return t-100 or something ...