Questions tagged [numerical-value]

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

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Prime sign ` followed by numerical values [duplicate]

Here are 2 lines of the numerical output of Mathematica: -0.0021055211287945152282575757575757575812.493743372412704 0.0282098170963017582537878787878787878913....
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Techniques to solve complicated simultaneous equations

I want to solve 5 equations simultaneously for 5 variables (N2[t],TT[t],PP'[t],SS'[t],z1'[t], code attached at the end of the post). The equations are extremely long and complicated. I have tried ...
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What's the best method to use when NIntegrating a sinx + cosx type function?

I'm having some problems when trying to NIntegrate a sinx + cosx type function. I have already tryed several combinations of ...
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2 votes
1 answer
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NSolve Having No Output

I am trying to solve a series of equations using the NSolve function, but am receiving no output. I tried to make the equations into a single equation, but this also doesn't work. I was hoping for ...
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How to numerically integrate with unknown coefficients?

will it be possible that I could integrate the equations like the following with unknown parameters M and h? I find it really hard. Any advice will be really appreciated, thanks. ...
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ParametricPlot3D Curve and ImplicitRegion: Projections and Intersections

There is a parametric 3D-Curve: ParametricPlot3D[{Sin[t], Cos[1 - 3 t], Sin[2 t - 1]}, {t, 0, 10}, BoxRatios -> {1, 1, 1}, AxesLabel -> {x, y, z}] And ...
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Solve an equation

I have this equation in terms of x0 and I need to find x0 in terms of Theta . ...
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Nature of function as $ x→∞$ [closed]

I'm studying the limits and applicability of Abel Plana summation for different test functions (class of functions). In doing so this just pops out and couldn't handle the said integral so asked here (...
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How to obtain the convolution of these functions?

I am starting to use Mathematica. I wanted to compute $$\nabla F*\phi(x),\;x\in\mathbb{R^2}$$ where $F(x)=\ln\|x\|$ and $\phi(x)=\chi_{B(0,2)}(x)$. I am a new user of this software, so I don't know ...
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Is the result given by NSolve sufficiently reliable to claim that there is such a solution for the equation?

I use this code for ContourPlot ...
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Optimising eigenvalue matrix calculation

I'm quite new to mathematica and am trying to figure out how to optimise my code as currently it takes a very long time to compile and makes it hard to bug test. The first part that creates the graph ...
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NSolve and FindRoot give a value which is not correct; how can I obtain the exact solution of the given equation? [closed]

I have two functions $ f(x,y) $ and $ g(x,y) $, I use this code ...
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Why the substraction of two big numbers does not yield 0, but taking their quotient yields 1?

I have two series, generated as, ...
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How to split data in a matrix

Consider the matrix 'm1' : m1 = RandomReal[{0, 1}, {50, 50}]; MatrixForm@m1 The partition of this matrix into non-overlapping rectangles (arranged horizontally) ...
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NSolve for Piecewise function

I have a piecewise function. I want to find the root of this function with the NSolve command. But, it does not give me any result and it just prints the equation. I can find the root with FindRoot, ...
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Numerical Integration and Fractional Decomposition (Apart) [closed]

Suppose we want to perform the following integral: $$I=2\int_{-1}^{1}f(e_0,s)g(e_0,s) \mathrm{d}s$$ with: $$f(e_0,s)=\frac{16 s^2 \left(2 s^2-1\right) \left(8 s^4-8 s^2+1\right) \left(8 s^2 \left(8 s^...
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Numerical integration with poles

I have got many errors for this integral. Anyone knows how to fix it? (I am using mathematica12.2) ...
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How to get numerical value of functional derivative at specific point

I have a functional in the form: $$F[s(x)]=\int_0^1(s(x)-a(x))^2\mathrm{d}x$$ where $a(x)$ is a parameter function, and I would like to find the functional derivative of $F$ with respect to $s$. ...
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Double numerical integral, in two steps

Let me define the following function: f[x_] = x I have to solve the numerical integral: ...
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1 answer
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Smart way to do a numeric integral of a recursive function defined by symbolic integration

I have a little question. I need a smart way to compute a numerical integral. The standard way to compute a numerical integral, in multiple variables, is, for example, the following: ...
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3 votes
2 answers
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Numerical values of Fox H function

I am playing around with the new function from 12.3, FoxH and found the result is not stable. It is interesting that the results are pretty different with the introduction of higher accuracy, and the ...
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1 answer
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Numerical integration of a function with Dirac delta

I have a little question about the numerical integration of a function that includes a Dirac delta. I have the following function: ...
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1 answer
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Which one is more accurate Solve or NSolve? How can I get the same result as Solve using NSolve in the given code?

I am using this code to calculate the quantity $sol$. Using Solve, I get the result $9.8598$ ...
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NMinimise for piecewise objective function with decision variable in the limit/present in the condition

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Getting strange result with derivative of Abs of a complex number

So I am getting some results after a computation like: (-0.741446 - 5.47358 I) Abs'[-0.702207 + 0.0951203 I] The problem is the derivative in ...
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3 votes
2 answers
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Blank plot with numeric data

I seem to be getting a blank plot even though the data provided is clearly numeric and plots fine with other data. I just don't see what is special about this data that results in a blank plot. ...
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Why does Mathematica store numerical values in a fresh kernel?

For some reason, when I try to do a computation in a fresh kernel, MM remembers the "old" values from the old kernel, is there a way to stop this?
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How to numerically solve this system?

Our system: \begin{align} \dot S &= \mu -\beta_1 S I_2 -\beta_2 S J-\beta_3 S A - \nu S\\[2ex] \dot {I_1} &= p \beta_1 S I_1 +q \beta_2 S J +r \beta_3 S A + \xi_1 J- b_1 I_1 \\[2ex] \dot{...
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Is always possible to define a numerical value using subscript?

In this code I defined some values using subscripts and it is not the first time I did this but strangely the code execution crashes. To follow the code. ...
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Avoiding underflow with equations of the form $\binom{n}{x} p^a (1-p)^b$

I have the need to evaluate equations of the form $$\binom{n}{x} p^a (1-p)^b$$ where the values of $p$ are between 0 and 1 and $n$, $x$, $a$, and $b$ can be very large numbers. I attempt to use ...
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what's wrong with this code for truncation number m=9?

I have a puzzling problem over the following mathematica code I program to solve some problem. I believe the two plots as defined are identical, but it is only identical when mm<9 and when m is ...
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Problem with numerical ConjugateTranspose?

Suppose I have a normalized numerical array, B1, ...
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NSolve not giving a solution

I have a parameter set paramFinal2 = {\[Beta] -> 0.2, \[Alpha] -> 0.5 , c -> 0.150, b -> 0.1, \[Kappa] -> 1}; I define the following variable ...
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Can't create matrix function of symbolic functions and assign values to elements

So I have a problem regarding the symbolic matrix value assignment. Say I create a matrix function as: P[t_]:= {{P1[t]}, {P2[t]}, {P3[t]}}; Then I want to assign ...
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Numerical minimization of function

So I have the following equation: 3 Sqrt[9.15753*10^-6 + 25.1556 TolC^2 + 25.1556 TolL^2]==1; Now TolC and TolL can take respectively the values of these lists: <...
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Evaluate an expression with numerical values

I hope this time you guys can help me. I have the following numerical expression: ...
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1 vote
2 answers
115 views

Efficent ways to use NSolve, Reduce

hope you're having a nice day! Context: I'm trying to constrain parameters from a model of Orbital Resonance equilibrium. In short, I know a parameter "$\Delta_{eq}$" which is derived from ...
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3 answers
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Finding the Global Minimum

Consider the function ...
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Is there any alternative for NSolve or Solve to obtain all the roots of the given function?

I have this function for reals $0<x<\pi$. $$f(x)=(3 \pi -2 x)^2 \sin \left(\frac{1}{2} \left(\csc ^{-1}\left(\frac{4 \pi (\pi -x) \csc \left(\frac{\pi ^2}{\pi -x}\right)}{4 x^2-8 \pi x+5 \pi ^...
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How can I make sure if the given function has any roots which are not rational multiples of $\pi$?

I have this function for $0<x<\pi$. $$f(x)=(3 \pi -2 x)^2 \sin \left(\frac{1}{2} \left(\csc ^{-1}\left(\frac{4 \pi (\pi -x) \csc \left(\frac{\pi ^2}{\pi -x}\right)}{4 x^2-8 \pi x+5 \pi ^2}\...
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NMaximize computes wrong value

This question is a continuation of NIntegrate with a complicated function over the 4-sphere . Now I define a certain new function called "improvement" via: ...
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How to extract the numerical values in the tables

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1 answer
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Phenomena between ill-conditioned and well-condtioned

Given that I have the following sparse matrix: ...
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1 answer
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how we can extract the value of the solution of a PDE in a point x? (NDSolve) [closed]

Please I need your help, I calculate the solution of heat equation using methode of line This is my code: ...
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1 answer
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Indeterminant numerical value of summation

I have the following two-fold summation. ...
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2 answers
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How to improve the calculation accuracy and speed of double numerical integration?

I want to solve the following double numerical integral: $A=\int _{0.52}^1\int _0^{\infty }\frac{\sqrt{s^2-0.52^2} \sqrt{1-s^2} \left(2 s^2-1\right) \left(\left(2 s^2-1\right) \text{T1}-2 s^2 \text{T2}...
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Nested NIntegrate over a region: Numerical Integration not converging

I need to computed two double nested numerical integrals, of which one is defined over a specific region (e.g. a pentagon). I've tried to use a single NIntegrate with four variables, but the result is ...
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1 answer
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Function range with numerical method

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2 votes
1 answer
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Does this series converge or diverge?

Let us consider the series $\sum_{n=1}^\infty \frac {\{\sqrt n\}-\frac 1 2} n$, where $\{\cdot\}$ denotes the fractional part of a real number. On the one hand, ...
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(Urgent) NSolve not working and visualization of solutions

I want to solve a system of three equations and 3 variables numerically with NSolve, but it either takes an eternity and doesn't give me a result or it gives me an error message that the methods ...
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