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8h
comment how to calculate the coordinate of a point which depends on other points on a plane with specific distances
You'll need to provide actual data. But from what I can see the problem is likely to be overdetermined (too many constraints to satisfy).
1d
comment Why does Mathematica not go to specified order in series?
Interesting. Not sure if it's a bug or a feature. I'll take a look.
1d
comment Is there a function for nearest power of 2 in Mathematica like nextpow2 in MATLAB?
For integers there is IntegerLength[A, 2].
2d
comment Solving a system of equations over a custom domain
(1) You can use inequalities such as -1<=x<=1 a;ong with specifying Integers as the domain. (2) As worded, your system could be quadratic rather than linear. (3) What @Öskå said.
2d
comment Computational complexity of symbolic determinant
I think best possible is O(n^4) or possibly better with asymptoticvally fast matrix multiplication. Also there will be a factor to account for integer coefficient size. For a practical approach you might try doing it by explicit polynomial interpolation.
2d
comment Ordering oscillators with negative powers: Infinite loops
From the formula it appears that if you multiply both sides on the right by a then it should canonicalize, provided your canonical form puts daggered factors on the right.
Jul
23
comment How to measure cross sectional area of Tube
Here's an outline of a method. For a given center point do the following. (1) Find several (at least 5) boundary points. (2) Find the cylinder that best fits these points. (3) Find cross-sectional area. If you want to constrain the center and perhaps direction vector of the axis then you can use fewer points and you'll want to constrain the optimization problem for best-fitting cylinder.
Jul
22
comment Mathematica policy for correctness of results
@Vladimir Reshetnikov [Off topic for this query, but I can no longer comment on your response.] I have tracked that erroneous integral to a problem in Series and filed a fairly detailed report.
Jul
22
comment Numerical integration involving Inverse Normal CDF
You are invoking GExpExp inside the integral without giving it explicit parameters x and s. It thus won't evaluate to a number.
Jul
21
comment Mathematica policy for correctness of results
Were I not an Wolfram Research employee with a vested interest, I would vote to close the question. I see nothing to distinguish it from a troll. Feel free to offer enlightenment to indicate otherwise.
Jul
21
comment Mathematica policy for correctness of results
See also wolfram.com/legal/agreements/…
Jul
17
comment How to estimate the matrix condition number in the 2-Norm?
You can estimate the L_infinity condition number of a square matrix via LUDecomposition (the third part of the result is that estimate). For the 1-norm take the LUDecomposition of the transpose.
Jul
17
comment How to solve equations over polynomial rings
Are you sure you want P4 both defining the ring and as a generator?
Jul
17
comment Balanced n-ary Base Representation
To expand ever so slightly on the point raised by @phosgene, you really need to provide a definition of this representation and indicate how it works.
Jul
16
comment Simulated Annealing for NMinimize[] always returning the same solution
Yes, this is the point of having that option. As for why it is not randomized by default, well, replicability is also useful and desirable.
Jul
16
comment Why DSolve giving Inconsistent or redundant transcendental equation on this problem
Nice analysis. As for the warning message, there is in effect a non-algebraic substitution for K$... inside the anonymous function f. The Solve code notices that a condition has been forced but does not then recognize that this condition is in fact implied by the input. Leaves a bit to be desired but it's the kind of thing that happens when we get outside of polynomial systems.
Jul
14
comment Is there is a design problem or documentation problem with FirstCase?
Reported as a documentation error. (As for how it was obtained, I believe there was a time during not-so-distant development when the default value was handled as an option instead of optional argument.)
Jul
11
comment Truncating out higher order polynomials in series of fractions
PolynomialReduce is a good function for this type of thing.
Jul
8
comment Integro-differential equation
I don't know if this will help but there are a number of other posts, some with responses, in regard to handling various integral equations. (That said, I'm not sure if any contained partial integro-differential equations.)
Jul
7
comment How to track row swap in Gaussian elimination?
It's not clear what "original rows" would mean. Gaussian elimination adds linear combinations of rows so a given final row can have parts of multiple original rows.