How to manipulate expressions structurally, not necessarily complying with the rules of algebra.

learn more… | top users | synonyms

6
votes
0answers
112 views

Using FunctionExpand to evaluate symbolic derivatives

Some symbolic derivatives of certain special function are not expanded automatically, but FunctionExpand often helps to get a derivative-free closed form ...
6
votes
0answers
114 views

How to convert a notebook cell to a string retaining all formatting, colorization of identifiers etc?

I have an opened Mathematica notebook containing several cells. Suppose, I am interested in one of them -- it may contain a complete or incomplete expression (e.g. with syntax errors, highlighted ...
3
votes
0answers
50 views

How to combine DifferenceRoot objects for odd and even-indexed terms

I'm trying to analyze a certain infinite sequence $S$, indexed by positive integers starting from $1$. It can be split into two subsequences: $S^{odd}$ by removing all even-indexed elements and ...
3
votes
0answers
143 views

Why doesn't Log[Gamma[]] simplify to LogGamma[] where it could?

I have been playing with various equations involving amount of permutations in relatively large sets. Easiest way to look at these is something like Log[10, bignumber!] . Often expressions, even ...
2
votes
0answers
140 views

Strange behavior of undocumented RawArray and ArrayObject expressions

I discovered several strange results and inconsistencies while trying to understand what undocumented RawArray and ArrayObject ...
1
vote
0answers
32 views

Matching Root[…] objects with patterns, unexpected hidden argument

I needed to write patterns that could distinguish between arbitrary-function and polynomial forms of Root objects, for example, ...
1
vote
0answers
221 views

Can mathematica simplify an expression setting simplified answer equal to zero?

Basically I want to reduce something like: Subscript[P, 4] - Subscript[P, 5] == Subscript[R, 4, 5]* Subscript[i, 4, 5] when only one of them is known (...
0
votes
0answers
81 views

Writing polynomials in standard form in a matrix

A symbolic matrix with two parameters, say $x,y$, shows up in my calculation. The entries of the matrix are homogeneous polynomials. I want the entries to be written in some standard format, e.g. in ...
-1
votes
0answers
23 views

How to easily and automatically transform recurrence equation to difference equation and back?

Recurrence equation is an equation that involves $f(x+1)$, $f(x+2)$, $f(x-1)$ for an unknown function f. Such equations can be represented in the form of finite differences, involving $\Delta f(x)$, ...