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Nov
27
comment How do I plot a line delineating a subset of values on a 3D surface plot?
I'm glad to hear it. You can accept the answer by clicking the checkbox to the left if you want to indicate that it solves your problem.
Nov
26
answered How do I plot a line delineating a subset of values on a 3D surface plot?
Nov
26
comment Building bounded polygon around heatmap (or points)
"Areas where the histogram is more than some threshold value" Have you considered ContourPlot or RegionPlot applied to a SmoothKernelDistribution? After all, a SmoothDensityHistogram is basically a DensityPlot of the SmoothKernelDistribution of the data.
Nov
25
comment How do I draw a pair of buttocks?
This is the first answer on this site that has literally made me go "what the f—" out loud. So congratulations for that.
Nov
25
comment How do I draw a pair of buttocks?
If only ExampleData[{"Geometry3D", "Beethoven"}] was a full-body model, a judicious use of PlotRange would do it.
Nov
24
comment Plotting phase portrait from NDSolve (i.e., must plot x'[x], where $x=x(t)$)
In that case, you should edit your question, because "I want to plot $θ(t)$ and $θ'(t)$, over the range, say, {t, 0, 100}" is precisely what ParametricPlot is for. ParametricPlot[{θ2[t], θ2'[t]} /. sol, {t, 0, 100}]: i.stack.imgur.com/MAgJO.png
Nov
24
comment Plotting phase portrait from NDSolve (i.e., must plot x'[x], where $x=x(t)$)
If you want to plot $\theta'$ vs. $\theta$ for a specific known solution, what you want is not StreamPlot, it's ParametricPlot.
Nov
23
answered Parametric contour plot?
Nov
23
answered List(Line)Plot with a big jump
Nov
22
comment List(Line)Plot with a big jump
Insert a Null (or anything that's not a real number) where you want a gap. ListLinePlot[{{0, 0}, {1, 0}, {2, 0}, Null, {3, 5}, {4, 6}, {5, 7}}]
Nov
22
answered Interpolating a polynomial for with first and second derivative of points
Nov
22
comment Interpolating a polynomial for with first and second derivative of points
Then InterpolatingPolynomial[{{r1, y1, yp1, ypp1}, {r2, y2, yp2, ypp2}}, r] will do it. It returns the polynomial of minimum degree that satisfies the conditions, and since you have six conditions, you will automatically get a fifth-order polynomial.
Nov
22
comment Interpolating a polynomial for with first and second derivative of points
You don't have $f(r_1)$ and $f(r_2)$, only its derivatives?
Nov
22
comment What extrapolation method does Interpolation use by default?
By the way, "With cubic spline interpolation, the second derivative at the end points is zero" is only true for what are known as "natural" cubic splines, which are not the only possible type of spline. In any case, Mathematica does not use spline interpolation by default, but even when you specify Method -> "Spline" it doesn't use natural splines.
Nov
21
comment How to make hollow octahedron 3-compound?
I was sure this was a duplicate of an older question, but it's actually not...
Nov
21
comment Implement a piecewise function elegantly and efficiently
I believe your function is also equivalent to Clip[0.5 x, {Max[xmin, x - m], Min[1, x + m]}].
Nov
21
comment Mystifying failure of NonlinearModelFit
Providing a ballpark initial guess works for me: NonlinearModelFit[ts, a Exp[b t], {a, {b, 1/800}}, t]. Doesn't work with Method -> "NMinimize" though, which ignores it.
Nov
21
comment Implement a piecewise function elegantly and efficiently
You can use Piecewise, which is designed to match the syntax of the mathematical definition-by-cases you wrote above. Although I don't know if there is any difference in performance.
Nov
20
comment How to plot curves in ternary plot (triangular plot)
Indeed, I believe István Zachar's answer in particular would work perfectly for this question.
Nov
20
comment How to check if a line segment intersects with a polygon?
Oh, yes it does. By "as expected" I meant "as in your answer". Yes, it does look like a bug. RegionDimension correctly returns 1, though.