Questions tagged [expression-manipulation]
How to manipulate expressions structurally, not necessarily complying with the rules of algebra.
809 questions
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9
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Reducing a symbolic expression to only its lowest-order terms
Suppose I have an expression which is a collection of symbols and integers arbitrarily combined with Plus and Times. For example,...
- 165
3
votes
2
answers
104
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2
votes
3
answers
309
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Simplification of terms C Exp[a+b x] to C Exp[a]Exp[bx]
I have an expression of the form
C1 Exp[a1+b1 x] + C2 Exp[a2+b2 x] + C3 Exp[a3+b3 x] + ...
Where variables C, ...
3
votes
1
answer
117
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Replacing fraction (rational number) inside Hold
How can be a fraction inside Hold replaced?
Nothing of the following works:
...
- 38.5k
5
votes
0
answers
105
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Avoid MonomialList applying N to coefficients containing floats
For inexact coefficients MonomialList seems to apply N.
How to avoid this?
...
- 3,546
2
votes
1
answer
216
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How to Factor Constants with Multiple Variables
I have the following expression:
\begin{equation}
aX + aY + bZ + bT +cV + cU\tag{*}
\end{equation}
expr = a X + a Y + b Z + b T + c V + c U
where $ a, b , c$ are ...
- 667
0
votes
1
answer
130
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MatrixExp for SU(3); $U = \exp[-i \sum_{a=1}^{8} c_a \lambda_a]$
I want to compute matrix exponential of general SU(3) rotations, $U = \exp[-i \sum_{a=1}^{8} c_a \lambda_a]$ for $\lambda_a$ is the Gell-Mann matrices. For three combintations of $\lambda$ works fine ...
- 925
1
vote
3
answers
151
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Reorder indices alphabetically in each term of a sum where each term has unknown form but contains a specific pattern
I am looking for a generalization of the answer to this question. I have a sum of terms
term1 + term2 + term3 + ... + termN
I know that some of the terms contain a ...
- 355
4
votes
2
answers
270
views
Reorder indices alphabetically in each term of a sum
Here is a challenge for you. I have an expression that has an arbitrary number of terms that look like
...
- 355
1
vote
2
answers
152
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Swap all instances of two symbols in one expression
I have an expression like
expression = a[k] b^j c^k (k j)!
I would like to swap all instances of the symbols j and ...
- 355
0
votes
1
answer
151
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Expand product of sums to nested sum
Good day
I have this product of two sums
expr = Sum[(2 n + 3) a[n] Exp[I p n x], {n, c, d}] Sum[
Exp[I q n x] b[n], {n, e, f}]
And I want to expand it to a ...
5
votes
1
answer
176
views
From exponent of sum to product of exponents
Good day
I have an expression
Exp[m I (a (Exp[-I x] + Exp[+I x]) + b (Exp[-3 I x] + Exp[+3 I x]))]
I want to convince Mathematica to expand the exponent,
...
4
votes
1
answer
339
views
Simplifying Exp[I Mod[x, 2π]] to Exp[I x]
I have an expression involving
Exp[I Mod[x,2Pi]]
I think it can be simplified to
Exp[I x]
How can I convince Mathematica to do ...
0
votes
1
answer
154
views
Solving ODE, why Mathematica gives more complicated results than Maple? [closed]
I don't know why this question was closed. The notice indicates this is due to "simple mistake" or something that could be easily found in documentation. I don't think the question falls ...
- 33
1
vote
1
answer
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Expression manipulations on similar expressions give different simplified expressions
Start with this list of two expressions :
...
- 613