# Questions tagged [numerical-value]

Question relating numerical representations, operations and methods, including approximate results instead of exact symbolic results.

28 questions with no upvoted or accepted answers
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364 views

### How does NSolve find the roots to an equation?

I'm using NSolve to find the roots to a transcendental equation. For this, I need to specify a bounded region where roots are searched. What I want to know is how <...
552 views

### Recognize physical constants?

Is there some way to ask Mathematica to recognize physical constants, such as 32 or 9.81 (gravitational acceleration, in different units, at Earth's surface)? I have in mind something like the "...
182 views

### On Ж, and the fine-structure constant

I'm trying to reproduce the results from a certain infamous paper that has been moving around the web for the last few days. The details are irrelevant. This paper claims to have a closed-form ...
112 views

### How solve this equation and plot the results?

I want to solve the following function and get values for $\omega$. $$\omega - \omega_{21} + i/\tau_{2} - s_{1}\alpha_{1}(\omega)[1+f(\omega)] = 0$$ The function $f(\omega)$ is the troublesome ...
67 views

### How to convert a dollar fraction into a normal dollar amount

I'm trying to use Mathematica to compute compounded interest. I used Wolfram Alpha, and it gave me the code ...
51 views

### Differences in AbsoluteTiming for similar codes

Consider the two following codes with the same SeedRandom (which ensures the same set of random numbers) but different use of the ...
44 views

### Exponential distribution and numerical errors?

I am working on the measure of a Curie Weiss model over a lattice $$\mu[m] = \frac{e^{\beta N (hm + m^2)}}{\sum_z e^{\beta N (hz + z^2)}}\binom{N}{\frac{(1-m)N}{2}}2^{-N}$$ where \$m\in\{-1,-1+2/N,\...
41 views

### Finding zero linear combinations of polynomials (numerically)

I have two functions of real variables defined on two compact spaces ...
84 views

### Plotting the Full width at half maximum as a function of a parameter

I have this function and I want to plot the FWHM of it as a function of the parameter "a", defined between 0 and 10. It should look like the picture attached. I also put the original equation in case ...
104 views

### Using Classifier with NearestNeighbors methods

I am using a Machine learning toolbox on mathematica. I have 8 classes. Training data: for each class, there 100 samples with size 160. I used this code. ...
52 views

### NIntegrate with highly oscilatory result

I want to evaluate a function defined by the following numerical integral: ...
64 views

### Strange behaviour with EllipticTheta functions

For some time I have been using EllipticTheta[3,-,-] functions, and to me it seems that Mathematica is really not handling them in the best way. Below are two of ...
35 views

### Nintegrate providing results much smaller than what is expected

This is the first time I am posting something here. So, apologies if I make any mistake. I am dealing with a numerical integration in Mathematica-11.0 that has a Bessel function in it. In order to ...
63 views

### Numerical evaluation expression not returning result in requested precision

I have a long list of descriptive statistical quantities for a univariate list of data. The problem is that the set number of significant figures is ignored by the ...
28 views

### Preventing mathematica from evaluating “Sort” function, except in the case of numerical values

Say I want to sort the eigenvalues E1, E2, and E3 using "Greater" as following: {EA, EB} = Sort[{Chop[E1], Chop[E2], Chop[E3]}, Greater][[{1, 2}]]; But I want ...
35 views

### Problem with NMaximize and intervals

My expression is ...
112 views

### Using NDSolve for differential equations

I'm trying to numerically solve the following differential equations eqs for plotting the bifurcation diagram. However, under special values of the parameter u, I get a problem when calculating the ...
195 views

### Evaluate and Plot x=x+1

I have a function of the form x=x+dx, whereas x(z) and dx(x,z) both depend on a increasing integer. Now I would like to evaluate this function after n time steps. In addition to that I'd like to plot ...
53 views

### How to time shift x-axis in mathematica simulation?

I have a simulation from a system of equations that runs from 0 to 50 Normal = NDSolve[{A /. Parameter, A[0] == .1}, {A[t]}, {t, 0, 50}]; That produces: Now ...
209 views

### Clebsch Gordan coefficients

I'm trying to compute various sums which contain some CG coefficients, where the sum runs over the indexes m1,m2,m corresponding to each of the three angular momenta j1,j2,j. The thing is that when I ...
65 views

### Integrate a multivariate function similar to a delta function

I am doing a code in Mathematica. I have the following function: ...
98 views

### Change of variables in integral is not working

Consider the matrix ...
46 views

### Error caused by ThreeJSymbol

I do not understand what causes non-physical answer in my code although I have read about the error. I am also getting the following error, how could I fix the example error: "CompiledFunction::cfte:...
63 views

### Evaluating expression with machine arithmetic gives wrong answer but evaluating with arbitrary precision works

I need to understand how Mathematica approximates symbolic numbers. I have an awful symbolic number to compute. When I do N[variable] Mathematica gives me <...
168 views

### Limit of a List

Is it possible to take the limit of a list instead of using the Limit method? I'll try to explain what I mean. I am generating a list of numbers that converge to some number. The generated numbers ...
133 views

### Problem with FindRoot + NDSolve + InterpolatingFunctionDomain

I'm trying to find the root (po) of a complicated problem (where s is a parameter): First, I need to define some functions, which involve numerically solving a differential equation. ...