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| bio | website | quantdec.com |
|---|---|---|
| location | ||
| age | ||
| visits | member for | 1 year, 5 months |
| seen | Jun 5 at 22:21 | |
| stats | profile views | 967 |
Consultant (environmental stats a specialty) and teacher.
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May 20 |
comment |
Problem with the Plot of Functions and PlotLegends What specifically is wrong with the output? |
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May 20 |
comment |
Solar System Orbital Parameters Just in case you are interested in accuracy, it might be worth noting that the system of ODEs described in your previous question at mathematica.stackexchange.com/questions/25039/… is not what is usually meant by an "n-body simulation," because it does not account for interactions among the bodies: it's just a collection of independent central field solutions. It might be a fine approximation for times close to the initial time but will be observably incorrect. |
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May 20 |
comment |
Find all the integer numbers $a$, $b$, $c$, $d$, $e$, $f$, $k$ to this equation have three integer different solutions? The question, which evidently is missing several words, now reads as if you are asking for all integral values of $a,\ldots,k$ in the interval $[-10,10]$ for which your equation has three distinct integral solutions. Is this a correct interpretation? |
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May 19 |
reviewed | Approve suggested edit on Im trying to find the eigenvectors of an 11*11 matrix but can't get it to recognise my data |
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May 19 |
reviewed | Close How can I connect to a SQLServer database without login details? |
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May 18 |
reviewed | Close Generating a list of all factorizations |
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May 18 |
reviewed | Leave Open Strange Behavior of NDSolve |
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May 18 |
reviewed | Leave Open Doing vector manipulations on Mathematica |
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May 18 |
comment |
Using single replacement rule to convert algebraic expression You might find Alternatives to be useful. |
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May 17 |
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Solving an ODE in power series +1 This is a good start. Power series solutions, though, are frequently used to obtain recursion equations for the coefficients (of any solution that might be analytic within a neighborhood of the point of expansion). It would be nice, then, to have a function that outputs these equations (given a differential operator as input), rather than just obtaining an approximate solution with a limited radius of accuracy. In order to analyze singular points, it would also be useful to consider slightly more general series of the form $z^\alpha(a_0+a_1z+a_2z^2+\cdots)$ for non-integral $\alpha$. |
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May 16 |
reviewed | Close How to tell Mathematica to make assumptions? |
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May 16 |
reviewed | Leave Open Using ImageTransformation[] with a lookup table |
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May 16 |
reviewed | Close Strange Error in NDSolve |
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May 16 |
reviewed | Close List of Tribonacci Polynomials with Mathematica? |
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May 15 |
comment |
Integration of a rational function Alternatively, use the Residue Theorem. Implicitly assuming $b\gt 0$ (WLG) and $c\gt 0$, we may (very quickly) obtain the solution as 2 \[Pi] I Sum[Residue[(a + x)/((b^2 + (a + x)^2) (1 + c (a - x)^2)), {x, z}], {z, {b I - a, I/Sqrt[c] + a}}] // Simplify, yielding $\frac{2 a \sqrt{c} \pi }{1+2 b \sqrt{c}+4 a^2 c+b^2 c}$. |
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May 15 |
revised |
How to deal with zero in NDSolve in mathematica? added 94 characters in body |
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May 15 |
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How to deal with zero in NDSolve in mathematica? That completely changes the question! |
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May 15 |
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How to deal with zero in NDSolve in mathematica? +1 This argument can be made rigorous by considering the approximate differential equation as a perturbation of the original. Applying DSolve with initial conditions is not very persuasive. It's more insightful to omit initial conditions: the solution will include a Bessel function of the second kind. This captures the singular behavior at the origin and approximates the singular behavior of the original equation there, too. Standard theory shows that's all the solutions you can have--just two dimensions of them--and then the rest of the analysis goes through as shown here. |
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May 14 |
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How to deal with zero in NDSolve in mathematica? The equations are inconsistent with the initial conditions. At $t=0$ you are requiring that $0 = t y'(t) = -x(t) - t \exp(x(t)) = -1$ which is impossible. |
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May 14 |
reviewed | Reviewed draw a graph of a polynomial function with variables in the denominator |
