Questions tagged [symbolic]

For questions about symbolic computation, as opposed to numerical computations.

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votes
1answer
43 views

Simplifying symbolic expression with Heaviside step function

When inputing Integrate[HeavisideTheta[s - t], {s, 0, 1}, Assumptions -> {t > 0}] Mathematica correctly simplifies if to -(-1 + t) HeavisideTheta[1 - ...
3
votes
2answers
45 views

Limit of an infinite summation

The above is from Maple 2019.1. Is there a way to achieve the same result from MMA12? Tried Limit[Sum[Sqrt[1 + k^2/n^3] - 1, {k, 1, n}], {n -> Infinity}] ...
2
votes
1answer
110 views

Solving infinite coupled equations

I need to solve symbolically an infinite system of coupled algebraic equations that I tried to do analytically but I could not. Solutions of these equations, $V_l^m$, define the coefficients of a some ...
0
votes
1answer
46 views

Get Mathematica to factor constants out of definite integral [duplicate]

Say we have Integrate[a f[x],{x,-Infinity,Infinity}] And want Mathmatica to factor out a to get ...
0
votes
0answers
105 views

Need help with symbolic integration

I have f[x_] := g[x]/g'[x] FullSimplify[Integrate[f[x], x]] I'm trying to get F[x] in terms of ...
2
votes
3answers
378 views

Symbolic Discrete Fourier Transform (DFT), using FFT?

Is there an implementation of a symbolic FFT in Mathematica? I've looked around, but I can't find any; Fourier seems to only give numerical results.
1
vote
1answer
38 views

Symbolic equation pair with two unknowns [on hold]

I am a beginner with Mathematica, so hopefully my problem is clearly presented. My problem is solving two unknowns from equation pair with five symbolic parameters. Baghdadi et al. (2016) created ...
15
votes
2answers
415 views

Factor a polynomial Root into Roots of smallest possible degree

Suppose I have a polynomial Root representing an algebraic number. I want to represent it as a product of several polynomial Root...
0
votes
1answer
68 views

Matrix of functions

I want to create a matrix of functions. As explained in this question, I can create a matrix of variables: ...
4
votes
1answer
53 views

find a maximum parameter for a range of target eigenvalues as a function of matrix dimension

I have a symbolic tridiagonal matrix of this form ...
44
votes
1answer
4k views

Analogue for Maple's dchange - change of variables in differential expressions

Maple owns an interesting function called dchange which can change the variables of differential equations, but there seems to be no such function in Mathematica. ...
1
vote
1answer
89 views

Replacing one of the integrals in the multiple integral with an analytical solution

Problem consist in simplifying complicated multiple numerical integral, where I know analytical solution for a subset of them. Integrand is of the form ...
2
votes
2answers
44 views

How to obtain a variable in terms of another variable?

I'm new to Mathematica and would like to ask a question about equation systems. I have a linear equation system given in the link. I would like to obtain kappa1 in terms of psi1, kappa2 in terms of ...
15
votes
2answers
898 views

Does anyone have experience with performing symbolic regression using Mathematica?

I understand that there is at least one Mathematica package, DataModeler commercially available for symbolic regression. I'm seeking any observations with this or any other similar tool. I'm ...
1
vote
1answer
91 views

Small error on symbolic eigenvalue of $2\times2$ matrix

I have some computation where I specifically define a 2x2 matrix to have a specific eigenvector v associated with an eigenvalue g, and a second eigenvalue l : ...
1
vote
1answer
28 views

Mixed partial derivatives with respect to n variables

I have the following generic set of variables: x = {x1, x2, ..., xn} nu = {0, 1, 2, ..., n - 1} order(nu) := Total @ nu; I would like to calculate: $$ \frac{\...
2
votes
1answer
47 views

Implementing the Peano-Baker Series with Mathematica

I would like to calculate the Peano-Baker series with mathematica, namely an integral expansion to approximate the state transition matrix: Say I have a matrix $A(t)$ and I want to calculate: $\Phi(...
0
votes
0answers
40 views

Algebraic manipulation on removing common factor outside

d[i,j] and M[i,j] are elements of size arrays of size 2x2 After some manipulations I get this as Output ...
4
votes
4answers
110 views

Find maximum according to a parameter

I am new to Mathematica. I want to find the maximum of the functions: ...
0
votes
0answers
39 views

Analytically integrating bivariate Gaussian PDF

I have this somewhat complicated expression in terms of the following 8 variables (note: actually, $X$ and $Y$ are variables, and $a,b,c,d,e,f$ are longer expressions as a funtion two other variables, ...
0
votes
0answers
38 views

Why does Refine not use transformation rules for a user-defined function?

I defined a transformation rule for a symbol L that takes a sequence of numbers ...
1
vote
1answer
42 views

Generating examples by applying conditions to symbolic expressions

For example, Given a list of symbolic expressions: ...
7
votes
0answers
86 views

DSolve fails with four variables

How is that DSolve has no trouble solving this: DSolve[{ D[G[x1,x2,x3],x1]==0, D[G[x1,x2,x3],x2]==0, D[G[x1,x2,x3],x3]==0 },G[x1,x2,x3],{x1,x2,x3}] but it fails ...
1
vote
1answer
58 views

Subscript and superscript symbols for chemical calculations

I have some very unhandy, big equations which contain quantities like $n_{AB}(^{13}C)$, now i would like to adapt this notation also in Mathematica so I do not need to think of a new one. Is there a ...
4
votes
1answer
97 views

Symbolic multiplication of tensors

I am trying to do symbolic calculations on Pauli Matrix Algebra. I want to find some way of making CircleTimes[a,b] ** CircleTimes[c,d] map to CircleTimes[a.c,b.d] for every a,b,c,d. I would also like ...
2
votes
1answer
104 views

Evaluating an integral symbolically

I am trying to integrate following integral symbolically via integrate command: $$(0.09)\Bigg[1 + \Bigg\{ \int_{3t-4k-7}^{2k+7/3} (0.09) \text{exp}\Bigg(\int_{3s-...
0
votes
0answers
59 views

Reduce, Solve, RSolve for symbolic equations? Neither seems to work for my problem [closed]

I want to solve the followiwng system of equations: Through substitution I get: I want to solve this equation for P_t I tried the following: ...
0
votes
3answers
93 views

How can I calculate the expected value of the sum of “n” i.i.d. variables with any distribution?

Particulary, I would like to find the expected value of the sum of $n$ variables distributed like ParetoDistribution[1,1.14]. For example, this works for the sum of two vars with Gamma distribution: <...
2
votes
0answers
59 views

Trace function did not show the steps to the final answer

Trace[ FullSimplify[ 1/4 Sec[20 °] + Sin[10 °] + 2 Sin[10 °]^2 ] ] Mathematica gave the correct answer 1/2, but it did not show the final steps to arrive at 1/...
1
vote
2answers
90 views

Coefficient of power $p$ in polynomial expansion : Mathematica doesn't answer me

I would like to compute the coefficient in front of $n^p$ for a polynomial expansion. I wrote the following code: ...
5
votes
2answers
372 views

Turning arguments into exponents

I'd like to replace every instance of L[stuff], e.g., L[-1,-2,-2] in an expression with ...
2
votes
2answers
112 views

Is there a way to know which symbolic expression Mathematica used?

Take the following symbolic sum: Sum[(-1)^n/Factorial[2*n]*(Pi/2)^(2*n)*n, {n, 1, Infinity}] Mathematica answers me: $- \frac{\pi}{4}$ It is great, I have an ...
2
votes
1answer
130 views

Changing operator precedence

Is there a way to change operator precedence for built-in symbols? I'd like \[TensorProduct] (which I redefine to ...
1
vote
1answer
76 views

How to pass lists as arguments in NMinimize or FindMinimum?

The following code runs in Mathematica 12. But, I have two problems that I would like to solve: (1) How to pass a list as an argument to the function g in such a way that it can be used seamlessly ...
0
votes
1answer
28 views

TensorReduce causes “inhomogeneous dimensions” error

I want to use TensorReduce to realize the following property of wedge: ...
0
votes
0answers
67 views

Limiting solution space for symbolic algebra problems

I have a system of 12 quadratic equations with 12 variables (x11, x12, x21, x22, x23, x33, p1, p2, p3, ϕ, μ, τ) and several positive constants,w, q1, q2. ... > 0<...
10
votes
2answers
544 views

Make symbols atomic, without losing their type

So, I'd like to define a matrix M, that does not decompose into it's constituents when I do things like Tr[M], but I also want it's type to be retained. (By type, ...
3
votes
0answers
42 views

Symbolic formula from GeometricScene?

I'm trying to solve the following problem with GeometricScene What is the shortest circular arc of which the altitude above its chord is one? I have the following code: ...
4
votes
1answer
92 views

Triggering WhenEvent as a result of WhenEvent

I'm attempting to solve a dead-simple differential equation with events: ...
2
votes
1answer
102 views

Problem when solving differential equation [closed]

Can anyone tell me why do I have errors when I try the code below ? ...
0
votes
3answers
71 views

Expand and Simplify do not work for NonCommutativeMultiply

Expand and Simplify do not work for NonCommutativeMultiply[] then how do we expand an expression like (a+b)**(a-b) ?
2
votes
1answer
45 views

Is there a method to preserve order when matrix multiplying in Mathematica?

I know that commutativity can be preserved in Mathematica by using ** i.e. a*b can get printed as b a but if I use a**b then it will always be printed as a b. However, I am not able to implement ...
10
votes
2answers
599 views

Symbolic Integration along contour: branch cut problem?

Context Following this question on path integrals in the complex plane, having defined again a numerical and symbolic integrator along a path as ...
0
votes
1answer
50 views

Symbolic derivation of LU

I've been needing to derive some LU factorizations by hand, analytically, and i was wondering if anyone knew if it were possible to get Mathematica to do this symbolically so that I may be able to ...
0
votes
1answer
40 views

I am asserting a variable in Mathematica as Real yet it is not implementing it!

Element[\[Theta], Reals]; Ga = g; Gb = g*Exp[I*\[Theta]]; {{Conjugate[Gb], Ga}, {Ga, Gb}} I have a code as such for a matrix as given above. as ...
0
votes
1answer
42 views

Symbolic Resultant Too Slow/Keeps Running

Evalutation of the following cell, which includes the symbolic resultant, of two univariate polynomials in $x$, with parameters $a,b,c$ for the first polynomial (of degree 4) and parameters $d,e,f,g$ ...
2
votes
1answer
36 views

Construction of symmetric function / matching function argument patterns

[Edited for clarification after comment] Suppose that the function f is defined as the linear combination of several translated/reflected functions starting from the primitive f0[x,y,z] ...
4
votes
2answers
120 views

Solving symbolic equation for fraction of variables

Suppose there is an equation like this (overly simplified example): eqn1 = ui - ua r1 / (r1 + r2) == 0 How can I get Mathematica to "solve" the equation in terms ...
1
vote
1answer
28 views

How to change the form of the answer? [duplicate]

Reduce[x^2 + y^3 == z && x + 2 y == 3 z + 1 && x y z != 0, {x, y, z}] you get ...