# Tagged Questions

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

78 views

### Display position of expression as Tooltip

How could we display the position of any sub expression in an expression using Tooltip? This would be useful for example in order to locate the position of an ...
57 views

### Is it possible to match a sequence with multiple heads without using Condition

Suppose I have: expr = Times[2, a[x,r], a[y,1], c[z,0,0], d[w,m]]; If I want to match a sequence of expressions with the same head ...
200 views

### Finding coefficient in expression

I have expressions like these: ...
80 views

### Custom rules for expressions in export to HTML(Fragment)

ExportString[Grid[{{a, b}}], "HTMLFragment"] ...
77 views

### Is there some way to implement automatic TimeSeries extrapolation or series continuation?

I am working with a large number of TimeSeries of irregular length. This means that if I sum them, or compute the mean, it cuts off at the terminus of the shortest ...
91 views

### Check an Option without Evaluation

Consider the following: ...
155 views

### How to name a repeated pattern sequence inside Plus?

Here is a sample expression that contains a bunch of f and some other stuff: ...
59 views

### How do I use Replace All? [duplicate]

I have an expression: a + b 2^(1/2) + (c + d 2^(1/2))*I I want to replace each occurrence of 2^(1/2) with ...
95 views

### How to organize expression by symbols (like Collect), but apply different functions to each coefficient

I want to mimic the functionality of Collect[expr, {vars}, func], but with the following modification: The function f that is ...
37 views

### Replace function and its derivatives [duplicate]

When I have a complicated expression that depends on some variable, say, $f$, the following usually works ok: Expression ./ { f-> x^2 } But if $f$ is a ...
48 views

### Solving a trigonometric equation for all $x$ using constant coefficients

I want to find the coefficients $a$, $b$, $c$, etc. that make an equation like $a+bx=x$ true for all $x$, but for trigonometric functions of $x$. For example ...
96 views

### Count number of summands?

Consider fun = a+b+c+d/e If we want to get the number of summands, we can use Length[fun], which properly gives ...
82 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 ...
50 views

### Misunderstanding of Replace code

I am looking for the right way to replace $\delta \, \, \text{by} \, \, 0.05 \, \, \, \beta \, \, \, \text{by} \, \, \, 1.77 \, \, \, \text{and} \, \, \, n \, \, \, \text{by} \, \, \, 12$ in this ...
355 views

### Using FunctionExpand to evaluate symbolic derivatives

Some symbolic derivatives of certain special functions are not expanded automatically, but FunctionExpand often helps to get a derivative-free closed form ...
92 views

### How to update values of nested association using AssociateTo?

Saying we have an association: asc = <|"A" -> <|"a" -> 1, "b" -> 2, "c" -> 3|>|>; I want to updated values of ...
1k views

I have been working on picking expressions apart using Head and Part and encountered a little mystery. Consider the canonical ...
51 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, ...
449 views

### Summa package problem

I need to use the features of the Summa package but it doesn't work in Mathematica 9. It gives the error Cannot open UtilitiesFilterOptions My question is: ...
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 ...
48 views

### How to label outputs from Print [closed]

I have problem with Print in Mathematica. The data that I get from it, is not labelled so that I can use it elsewhere, therefore I have got to label them manually. ...
10k views

### Is it possible to change the color of plot in Show?

For example: p = Plot[Sin[x], {x, 0, 1}] Is it possible to write options in Show to change the curve's color for example into ...
99 views

### Extracting factors from an expression

I want to transform expressions into lists of elements. For example, b*c + a*b*c /. Plus -> List /. Times -> List ...
86 views

### Separate integer fractions from variables?

Whenever I write a rational number times a variable, i.e.: (2/3)a the result Mathematica displays looks very cringeworthy: $$\frac{2a}{3}$$ I would prefer ...
512 views

### How to replace the first Head of a currying expression like “a” in a[b,c][d]?

How do we replace the first Head of a currying expression such as a[b,c][d]? When accessing the ...
106 views

### When is the righthand side of a RuleDelayed evaluated?

The documentation on RuleDelayed states that lhs :> rhs represents a rule that transforms lhs to rhs, evaluating rhs only after the rule is used. Consider the following rule: ...
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I have this: ...
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### The role of comma in the syntax of Part

I can't understand the syntax of Part, namely what does , do. The documentation says that ...
55 views

### Replacing product of functions wih another function

I have a function which depends on w,x,y,z. Let me call ...
86 views

### ToExpression to Latex Parenthesis

Everytime I use ToExpression to transform a TeX expression into mathematica input form, Mathematica always interprets parenthesis ('(' and ')') as square brackets, ...
360 views

### Get rational and irrational parts

Consider an expression of the form $a + b \sqrt{2}$, where $a,b \in \mathbb{Q}$. How can I extract $b$ (or equivalently $a$) from this expression?
45 views

### Prevent Plus from reordering terms by default? [duplicate]

Writing Plus[a,b]//FullForm gives back Plus[a,b], while Plus[b,a]//FullForm again returns <...
161 views

### Simplify the huge determinant product

I try to get the following determinant product result, ...
40 views

### How can I rewrite this expression in terms of V_o/V_s?

\frac{V_o-\frac{A \left(R_{\text{int}} \left(V_s-V_1\right)\right)}{R_{\text{int}}+R_s}}{R_o}+\frac{V_o}{R_L}+\frac{V_o-V_1}{R_1}=\frac{V_1-V_s}{R_{\text{int}}+R_s}+\frac{V_1-V_o}{R_1}+\frac{V_1}{...
48 views

### Get dominant terms in asymptotic expansion

I'd like to find the dominant terms of an expression given the conditions $x,y >> 1$: $c_0 y+\frac{y^2 \left(4 c_0^2 y - 12 c_1 c_2^2+y^2\right)}{24 x^2 \left(\text{c1}^2+\text{c2}^2+y\right)}$ ...
81 views

### Can I map a function over a sequence of arguments without making the arguments into a list first?

I would like to set evenFunction[f_][a_, b_, c_, ...] = f[Abs[a], Abs[b], Abs[c], ...] I have come up with two ways to do this so far. Use pure functions <...
352 views

### Factoring out a common term

Very simple question, but I can't find a simple answer here or in the documentation. I have an expression: qq = a x + b x^2 + c x^3 and wish to factor out a ...
612 views

### Counting multiplications (complexity function)

I'm trying to count the number of times multiplication appears in an expression (for the purpose of constructing a ComplexityFunction that would help me simplify a terrible algebraic expression for ...
96 views

### How to neglect some part of an expression

I have an expression of the form $a\,x^3 + b\,x^2 + c\,x$ in my answer. I want to avoid those terms in my answer of order 1, but want to keep those of order > 1 in $x$. Can you suggest how to do in ...
312 views

### Derivatives of functions with arbitrary number of variables?

I am trying to define a function f[x1,x2,...,xn] with n integer but not specified. And then I would like this funktion to behave ...
188 views

### First order approximation

How can I neglect higher orders of approximation in Mathematica? Suppose I want to find the roots of a simple quadratic equation like ...
201 views

### SeriesData sucks when it can. How do I keep SeriesData from sucking?

When I run Series[f[x]*Sin[x],{x,0,3}, Analytic->False] I get: f[x](x-x^3/3+O[x]^4) as expected. In ...
109 views

### More simplification tricks in Mathematica? [duplicate]

I need to simplify the following expression in order to operate on it using InverseLaplaceTransform. This result will be used in further work, so ideally I would ...
51 views

### Extract list of values associated with specific header within an expression

I would like to have a function that can extract from an expression a list of values that are within the brackets of a certain header at any level: ...
55 views

### Avoiding misconversion of data with ToExpression function [closed]

I've got a list of data with the following structure which can be easily converted To expresion by some manipulation such as ...
42 views

### Manipulating form of output redux [duplicate]

To clarify the question that I posted here, I have the following question: I am generating a very large term by the following: ...
68 views

I evaluated ...
107 views

### Simplest identity that cannot be proved by FullSimplify [closed]

Apparently, FullSimplify is not able to prove all true identities, but usually it does pretty well when it comes to elementary functions. I'd like to know what are ...