# Questions tagged [symbolic]

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

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### Long computation time for solving two algebraic expressions

I am having two equations algebraic equations in two variables and 12 parameters However, the Solve command is failing to provide any result even after running it for 5 hours. How much time should I ...
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### Why can Mathematica detect a linear term in a series expansion only in special cases?

The series expansion Series[Sqrt[2 - 2 Cos[d k]], {k, 0, 5}] Is in odd powers of Abs[k], or more precisely ...
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### Minimize fails to find a minimum [on hold]

I am trying to find, analytically, the $\theta,\phi$ that minimize the function U($\theta,\phi$) ...
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### Exact Solution to Maximum with constraint, no output

I am new to Mathematica. I am trying to solve a maximum problem with several constraints. Here is my input. ...
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### Definite Integration with Exponental Heaviside Step Funtions

As part of an equation of state calculator that I am working on, I have to handle a virial expansion for the equation of state. As such I have to solve for the virial coefficent, $B(T)$, which is ...
51 views

### Assign Values from Array to Array [duplicate]

I am trying to simply do the following cVec = {a,b,c,d} From another expression, I obtain another vector, say, ...
36 views

### How to force Mathematica to give answer in certain functional form?

I want Mathematica to evaluate $$0=\psi (x) \left(\frac{k x^2}{2}-\text{En}\right)-\frac{\hbar ^2 \psi ''(x)}{2 m}$$ and give me answer in terms of the Hermite polynomials but it gives me result in ...
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Given: ...
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### Symbolic matrix equation with summation

Considering a set of points: Let Matrix A be: And B: Where $\bar{x}$ is given by: And the same goes for $\bar{y}$ and $\bar{z}$. I want to solve this equation: But without specifying any values. ...
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### Help speeding up solution of system of differential equations using Laplace transform

I'm trying to speed up this code that seems to take forever to evaluate. I'm solving a system of 9 coupled differential equations using a Laplace transform (a version of this code that works perfectly ...
83 views

### Is it possible to make Decompose work with coefficients containing radicals?

It appears that Decompose works reliably only on polynomials with integer coefficients, although it seems to be not mentioned in the docs. Can I make it work (or ...
34 views

### Integrate Twice over Symbolic Interval [closed]

I would like to solve: $$\int _0^1\int _y^11dxdy$$ In one function call to Integrate[]. However, evaulating Integrate[1, {x, y, 1}, {y, 0, 1}] (*1-y*) Gives ...
51 views

### How to multiply the elements of each site of tensor products to each other while using symbolic representation?

If I have, say three sites in a symbolic operator which is of the form A = a⊗1⊗c and I want it to act on another operator B = a1⊗b⊗1 in order to find the commutator A.B - B....
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### Why DSolve gives different answer depending on order of variables: $u(x,t)$ vs. $u(t,x)$?

Using V12 on windows 10. I would think it should not matter if one uses $u(x,t)$ or $u(t,x)$ in the specification of the PDE, as long as everything else is consistent (keeping the initial condition ...
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### How to set up a Fourier transform?

I am having trouble figuring out how to set up the Fourier transform to: ...
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### Get Conditions for Variable to be Real

I have a complex definition of a few variables (that I got using s = Solve[1 - a x^2 - x^3 == 0, x]) and I now want to know under what conditions of "a" will each ...
50 views

### How to define a cross product of two orthogonal vectors?

t[s], n[s] and b[s] are three orthogonal vectors. I define a cross product ...
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### Lambda calculus reduction in Mathematica

Are there any built-in functions for reducing lambda terms in Mathematica? If not, how might one do it? I've heard of Function, which is good for $\beta$-reduction, ...
38 views

### Replace sub-expressions matching a pattern unless located under specific heads

Suppose I have some rule, e.g. Re[x_] :> (x + Conjugate[x])/2. I want to apply it to all matching sub-expressions in some expression, excluding any sub-...
507 views

### How to evaluate $\int_0^1{\mathrm e^{\mathrm i\pi x}x^x(1-x)^{1-x}\mathrm dx}$ and get $\frac{\mathrm i\pi \mathrm e}{2\cdot3\cdot4}$?

The following definite integral identity holds $$\int_0^1{\mathrm e^{\mathrm i\pi x}x^x(1-x)^{1-x}\mathrm dx} = \frac{\mathrm i\pi \mathrm e}{2\cdot3\cdot4}$$ and is easy to verify numerically. ...
54 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}] ...
53 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 - ...
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### 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 ...
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### 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 ...
173 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 ...
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### Symbolic equation pair with two unknowns [closed]

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 ...
71 views

### Matrix of functions

I want to create a matrix of functions. As explained in this question, I can create a matrix of variables: ...
67 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 ...