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

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0
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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
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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 ...
2
votes
1answer
46 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. ...
1
vote
1answer
78 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 ...
5
votes
2answers
96 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 ...
7
votes
1answer
84 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 ...
7
votes
1answer
105 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: ...
10
votes
7answers
509 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 ...
5
votes
1answer
81 views

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 ...
1
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1answer
54 views

Replacing product of functions wih another function

I have a function which depends on w,x,y,z. Let me call ...
4
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1answer
77 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, ...
0
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0answers
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 ...
1
vote
1answer
39 views

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

$$\frac{V_o-\frac{A \left(R_{\text{int}} ...
0
votes
1answer
47 views

Get dominant terms in asymptotic expansion

I'd like to find the dominant terms of an expression given the conditions $x,y >> 1$: $c_0 y+\frac{y^2 \left(4 c_0^2 y - 12 c_1 c_2^2+y^2\right)}{24 x^2 \left(\text{c1}^2+\text{c2}^2+y\right)}$ ...
1
vote
1answer
80 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 ...
2
votes
1answer
289 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 ...
1
vote
1answer
159 views

Simplify the huge determinant product

I try to get the following determinant product result, ...
2
votes
2answers
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 ...
6
votes
1answer
180 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 ...
1
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1answer
49 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: ...
0
votes
1answer
52 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 ...
17
votes
1answer
197 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 ...
0
votes
1answer
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: ...
4
votes
0answers
105 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 ...
0
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0answers
61 views

Simplifying sums of rational trigonometric functions

After simplifying the trigonometric functions as advised before (cf. Simplifying Expressions for FindMinimum), I obtained a sum of 62 similar expressions, the first three as in the below: ...
4
votes
1answer
83 views

Returning all branches of a multiple-valued function

This question and answer was inspired by this closed as duplicate question. One possible definition of the n-th order root of x ...
6
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2answers
212 views

ReplaceAll problem

Bug introduced in 10.1 and persisting through 10.2 or later Confirmed, as bug, by WRI: [CASE:3402234] I am trying to combine terms of the type ...
21
votes
2answers
690 views

Given an exact formula, how can Mathematica find a probability distribution whose PDF matches it?

So, given some data, Mathematica 10.2 can now attempt to figure out what probability distribution might have produced it. Cool! But suppose that, instead of having data, we have something that is in ...
0
votes
1answer
71 views

Extract all elements of an expression in order into a list [closed]

I have and expression a + b + c - d and I would like to generate a list of {a, +, b, +, c, -, d}. I have tried ...
4
votes
5answers
135 views

Assigning the numerical results of Minimize to variables [closed]

I need to use the numerical values returned by Minimize in further computations. Consider, ...
0
votes
0answers
108 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 ...
3
votes
1answer
290 views

Separating exponential terms

Suppose I have a lot of expressions multiplied by factors such as: $$e^{-i\theta[1]-i\theta[2] - i\theta[3]-i\theta[4]-i\theta[5]}$$ I would like to separate this into a product of exponentials of ...
13
votes
1answer
279 views

ToExpression processing errors

Is their a way to get a more comprehensive return value when running ToExpression? For example when I run ...
2
votes
1answer
147 views

Select largest number using pattern

I have the following expression: myExpr=R[C[2],B].(II+R[C[3],C[2]].(II+R[C[4],C[3]])) I need to create a pattern which would replace the ...
-1
votes
4answers
107 views

Converting an expression to function [duplicate]

I have the following problem. I current can automatically create the variable positionPayload, for instance: ...
2
votes
0answers
79 views

Derivative of vector dot product with respect to a vector

I have the expression: Transpose[gvecI, {2, 1}].x (m[1] + m[2]) gvecI and x are [3x1] ...
2
votes
1answer
115 views

Simplifying Expressions for FindMinimum

I am currently trying to apply the FindMinimum function to find the lowest energy of an expression. My current expression as of now is relatively complicated. It is the summation of 48 similar terms, ...
-1
votes
1answer
53 views

Position not working? [closed]

I have the list: myList={0,0,0,a,b,c,0,0,d} I need to find the positions of all elements that are non-zero. I do like this: ...
3
votes
2answers
82 views

Find sub-sets of vanishing additions or subtractions from a list?

Let's say I have a list L containing n numerical numbers. Now I want to find all sub-sets of ...
2
votes
1answer
65 views

Dropping rational coefficients

I have a list of expressions (they all are exact numeric quantities, not containing any variables), some of them have integer or rationals coefficients, or complex coefficients with rational or ...
2
votes
2answers
77 views

Trouble simplifying using Replace

I have the following expression: w.a.b.r+w.c.d.r I want to get: w.(a.b+c.d).r So far I used ReplaceRepeated: ...
3
votes
1answer
148 views

What role to sub/superscripts play in Mathematica?

I'm not sure I understand the role of subscripts and superscripts in the Mathematica language. For me, the expression: ...
1
vote
0answers
59 views

How to remove parts of an expression

I have an expression where terms Transpose[R].R appear. R is a matrix with the property Transpose[R].R=IdentityMatrix[3]. How ...
4
votes
3answers
358 views

How to get a list of monomials of a polynomial without coefficients?

Giving a polynomial, say a x^2 + b x y + c y^2 MonomialList[a x^2 + b x y + c y^2, {x, y}] just gives ...
4
votes
1answer
59 views

Boundedness of an expression

First post on this part of the stackexchange network, I was just wondering if Mathematica allows one to quickly see if an expression is always within a certain range given values for the parameters it ...
3
votes
2answers
93 views

Factor a specific sub-polynomial?

Consider the following example for a polynomial in several variables: ...
1
vote
0answers
73 views

Sequence of arbitrarily many variables separated by commas? [closed]

I am wondering if it is possible to produce an input such as x[1],x[2],x[3],...,x[n] for an arbitrary but fixed amount of n ...
2
votes
4answers
208 views

Is there a way to use array of data as a function variable?

I have a data that looks something like. {{1,1},{12,1},{7,9},{10,14}, ...... } I want to see if there is an easy way to apply this array of data into a ...
3
votes
3answers
145 views

How I can count multiplications in an experssion?

Next task to complete: Count *-symbol in such expression as a + s^2*b - c/y + o^3 + n*m*u (in this case count of ...