# Tagged Questions

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

81 views

### Range and decimal digits [duplicate]

When I set Plot[Sin[x], {x, -2, -1}, Frame -> True, Axes -> False, FrameTicks -> {{Automatic, Automatic}, {Range[-2, -1, 0.2], Automatic}}] I ...
277 views

### Trying to write out the prime factorization of a number with CenterDot and Superscript

I am trying to use CenterDot and Superscript, in conjunction with Apply to write out the prime factorization of any given integer. Everything works well UNLESS the prime factorization of the number ...
346 views

### Concatenating strings, unevaluated expressions and evaluated expressions/values

Maybe this is something very simple to some of you. Anyway, I think this can be useful to many others like me. I would like to build an output that involves strings, unevaluated expressions and ...
252 views

### Keep Mathematica from simplifying functions with a specified Head

I want to run Simplify and/or Refine on various expressions, but keep it from touching anything that contains a specific ...
157 views

### Unexpected Behaviour with local variables and ToExpression

I encountered an unexpected behaviour in my mathematica-code, and want to understand whether that's a mathematica bug, or a misinterpretation on my side. ...
197 views

### Time-efficient creation of matrix

I have expressions like xx1=FF[1, 1] GG[1, 1] + FF[1, 1] GG[2, 2] + FF[2, 2] GG[2, 2] xx2=2*FF[1, 2] GG[1, 1] + FF[1, 1] GG[1, 2] + FF[2, 2] GG[2, 2] and I want ...
152 views

### Time-efficient manipulation (zeroing) of expression

I have huge matrices in the form of ...
94 views

### Problem with InverseFunction of Sqrt

I want to build a table of InverseFunctions, f.e.: ...
273 views

### How to get solution from DSolve

How to get the solution from DSolve in such way that there is no need to copy the result. When for example solving: ...
140 views

### How do I constrain variables to a user-defined domain in ArgMax?

I am trying to ArgMax a function over x, but x is only defined between ...
177 views

### How to get a list of all expressions in a notebook matching a certain pattern?

Suppose I have a Mathematica notebook saved to a certain location on disk. Given a pattern I need to get the list of all expressions matching this pattern that appear in input, output or print cells ...
61 views

I am currently trying to solve under what condition does the following term will be zero? ...
71 views

### How does one go from a string to the contents of a variable with the same name?

What command should I use if I want to convert a string to the contents of a variable with the same name as the contents of that string withing a function. ToExpression[] doesn't seem to do it. ...
192 views

### List of Coefficients of Expression with symbolic Terms

(I am affraid that this is a duplicate, but I read several already asked questions and non of them helped me. If it's already answered, please tell me) I have expressions like this ...
248 views

### Stopping Mathematica from reordering expressions [duplicate]

I want Mathemtica to stop manipulating my polynomials! I mean, I want the output of Print[3 x + 5 + x^2] to be just $3x+5+x^2$, not $5+3x+x^2$ as Mathematica ...
94 views

### Convert an expression from one form to another

I have this expression -0.433284-0.758719 x+0.00289158 x^2-0.443672 y+0.00149027 y^2 I want to express it in terms of $$\frac{(x-h)^2}{b^2}+\frac{(y-k)^2}{a^2}$$....
77 views

1k views

### How can I obtain Wolfram Alpha's “alternative forms” of an expression inside Mathematica?

When I type in Wolfram Alpha, say, cos(a+b) or cos(a+b)^2 or (OK this next one can easily be obtained in Mathematica, ...
237 views

### Extract data from DateListPlot, limited by PlotRange

Extracting the points from a line in a ListPlot in this answer uses points = Cases[Normal@plot, Line[pts_] :> pts, Infinity]; This works in DateListPlot (...
2k views

### How to completely delete the head of a function expression

Is there any way to completely remove the head of an expression function? For example, how would I remove the head Cos from ...
153 views

### Thread over uneven (ragged) expressions with full functionality?

There are a number of questions on this site about "threading" including several relating to uneven (ragged) lists. However, none that I could find deal with the full functionality of ...
80 views

### Converting expression to C

I have an expression of the form ...
62 views

### Quoting definition explicitly

I'm trying to quote a definition using DownValues, OwnValues, etc. Everything seems to be fine, except for temporary symbols' ...
228 views

### The most external subexpression with given pattern

Suppose there is a deep expression with several instances of some _f. I want to get the most external case of _f from it (I also ...
54 views

### Converting an expression to modular arithmetic automatically

I have the expression $\frac{1}{15} \left(-(-1)^n-5\times 2^{n+2}+3\times 2^{2 n+1}+15\right)$ which I want to calculate mod m for a very large n. My current method is to ask for this exression in ...
793 views

### List of atomic expressions

I was surprised to see Graph objects are atomic. Is there a way (through documentation or programmatically) to find all atomic heads? The ones I know of are: <...
709 views

### Truncate High order terms

Suppose I want to compute this : Series[Sin[1/f], {f, Infinity, 10}] but finally I prefer Sin[1/f] up to the fourth order in <...
88 views

### MapIndexed stops at levelspec 1 if only the index is passed?

If the function passed to MapIndexed references the first (or data) argument, the following performs as expected: ...
218 views

### Expand expression into quotient of negative power series

I have a function T(z) and want to expand it to the following form: At the end I want to have a list of equations, which can calculate a0, a1, a2, b0, b1 and b2 with different values of h1, h2, ...
2k views

### Scan vs. Map vs. Apply

I cannot understand the difference between Apply, Scan, and Map. I have tried to play with ...
54 views

### expression contained across multiple cells

Is it possible to span one expression across multiple cells? E.g. long if statement or function evaluation. I looked in documentation and searched forum/google and could not find.
294 views

### Replace every Minus to Plus in Expression

Thought this is a rather simple thing, but I was not able to find a solution: I have a polynomial expression like: expr1=a^2-b+c*d expr2=a-b expr3=-a+b-c and ...
107 views

### Mathematica: Extract the piece that contains x=0 from within a piecewise function

In mathematica, I have a piecewise function similar to: Piecewise[{ {x^2 + 2*x - 4, 0 <= x <= 1/4}, {0, true} }] I don't ...
85 views

I have this: ...
105 views

### Decompose Expression into Segments

Say I have an expression test = 3 x1^2 - 2 x3^-3 and I would like to decompose the expression into {3 x1^2, -(2/x3^3)}, I can do ...
90 views

### Working with functions

I am required to write a function that takes a function as a parameter. ...
164 views

### Patterns of function-arguments in expressions

I want a function that compares an expression with a specific pattern. The expression has always the following form: ...
240 views

### Extracting function calls from an expression

I have an expression like this: expr = F[0, 1] + 2 F[0, 0] - 17*F[2, 0] and I want to transform it to a list consisting of all function calls with its arguments: ...
129 views

### Merging two held expressions into a held compound expression

Consider e1 = Hold[a = x + x; b = y + y + y]; e2 = Hold[c = a + a + b + b + b; c^2]; How can I obtain the following? ...
110 views

### Why is ^^ff not the same as ^^ToExpression[“ff”]?

I want to convert a hexadecimal string to a decimal (base 10) number: 16^^ff 16^^ToExpression["ff"] The 1st line returns the correct answer of 255, while the 2nd ...
255 views

### Set gives an unexpected error message (Set::partw)

Here is a minimal example: s = 1 /(a + b[3]) + 1 /(2 a + b[3]); s[[1]] = Sum[s[[1]] /. b[3] -> k, {k, 3}] s[[4]] s[[4]] = Sum[s[[4]] /. b[3] -> k, {k, 3}] ...
112 views

### How to convert the expression '{a->a0, b->b0}' to the expression 'a=a0; b=b0'? [duplicate]

How to convert the expression '{a->a0, b->b0}' to the expression 'a=a0; b=b0'? I think this is a common question and do not know if someone has asked it before. Any help or suggestion will be ...
2k views

### How to extract expression from ConditionalExpression

p1 := y /. {First[Solve[x^2 + y^2 + x == 1, y, Reals]]} ...
143 views

### Selecting expressions from a sequence that are not subexpressions of earlier elements

I have a While loop that generates and prints an expression on each iteration (there can be thousands of iterations). UPDATE: Some expressions are generated in ...
189 views

### Partial result of aborted evaluation of FullSimplify

When FullSimplify invoked on a large expression, it can run for hours. If I do not have time to wait, and abort the evaluation, I get no result, although, ...
222 views

### How to collect expressions from cells created by Print?

I have a notebook where evaluation of a certain cell produced hundreds of adjacent output cells using Print. I need to create a list containing all expressions from ...
100 views

### check if the expression is a equation

I need to check if the expression is a correct equation with only 1 variable x and without functions, that are not build into Mathematica. For example Sin[x]==0 ...
85 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 ...