# All Questions

235 views

### Attempting to use NDSolve to plot harmonic oscillator solutions

NDSolve[{ (-y''[r]/1880) + (470 (0.04077)^2 r^2 - 48 + 1/(1880 r^2)) y[r] == 0, y[0] = 0, y'[0] = 0}, y, {r, -4, 4}] I use this but get errors and am ...
600 views

### How to define a vector with automatically added symbolic elements with subscripts

I want to define a vector lets say k containing elements Symbolize[Subscript[k, 1]], k2, k3 ... etc. When I define lets say k4 . I want the symbol automatically added to vector k. Something like ...
974 views

### NDSolve problems of convergence

I have a big function that I have to maximize, so I have to evaluate some equation with thousands of different values of the parameter. But the FindMaximum returns me many errors. I have traced the ...
531 views

### EdgeRenderingFunction question

Bug introduced in 9.0 and fixed in 10.0.0 (Edit 1 : I added this paragraph after the original post, for context) Some context for this question can be found in another post (http://mathematica....
112 views

### Incompability between v5-6 and v10 with Graphs and Oriented Graphs pkgs?

Notice that "although the v6 Packages are available at the link in the answer above they are not fully compatible with v10". The errors 1, 2 and 3 in Mathematica 10 student edition may be due to ...
989 views

### ParametricNDSolveValue or NDSolve + fitting

I have been trying to find the value for the parameter kestim that yields the best fit of a model to some data points. datac has ...
186 views

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### How to find intersection points of lines?

Considering I have three functions f1 = -x + 1; f2 = x - 1; f3 = x + 3; How can I find the intersection points of this functions? Thanks. This didn't work <...
860 views

### Using Array Elements as Function Arguments

Suppose I have an array p = {a,b,c,d} and a function f that takes a variable number of arguments. I want to evaluate ...
4k views

### Stategies to avoid NIntegrate::slwcon error

I am trying to numerically evaluate an integral whose integrand depends on two parameters, say $(a,b)$ and when $b\gg 1$ I suspect (although it's not guaranteed) that the integrand is very small. Thus ...
658 views

### Changing FrontEnd automatic scrolling in version 8

In Mathematica versions < 8, the FrontEnd has a very intelligent behavior: On evaluation, it by default automatically scrolls down the Notebook window to the last printed Output cell but also ...
423 views

### Unexpected result {“.a”, “co”, “.m”} from Sort[{“.m”, “.a”, “co”}]

I came across the following situation: Evaluating Sort[{".m", ".a", "co"}] Results in {".a", "co", ".m"} I wondering: ...
299 views

### Incorrect Timing of Total

For demonstrating how fast C-compiled functions can be, in one of my courses I use the following function for finding the sum of a list of reals: ...
6k views

### Plotting vectors originating from the origin in 3D

I have an array of data with 3D elements. Ex: x = {{1,2,3}, {3,4,5}, {5,6,7}}. I want to show this data in 3 dimensions, such that each point in the space is shown ...
1k views

### Insphere for Irregular Tetrahedron

I am looking for existing Mathematica code to compute the unique sphere inscribed inside an irregular tetrahedron. I can write it myself, but I would love to find that someone already performed this ...
611 views

### How do I introduce a new variable in a trigonometric equation?

I have the trigonometric equation \begin{equation*} \sin^8 x + 2\cos^8 x -\dfrac{1}{2}\cos^2 2x + 4\sin^2 x= 0. \end{equation*} By putting $t = \cos 2x$, I have \begin{equation*} \dfrac{3}{16} t^4+ \...
302 views

### RegionPlot returning a number

Bug introduced in 10.0 and persisting through 10.4 or later I had updated my mathematica to version 10 few days ago. And I had been shocked by the following fact: ...
271 views

### A bug in Commonest in version 10

Bug introduced in 10.0.0 and fixed in 10.0.2 m_goldberg demonstrated that in Mathematica 10 Commonest does not behave as the documentation indicates that it will....
951 views

### How to remove accents from text?

I would like to know how I can remove accents from a string. For example, how can I transform "string test áéíóú" into ...
324 views

### Why does Mathematica simplify $x/x\to1$?

If I enter x/x, I get 1. Such behavior leads to this: Simplify[D[Sqrt[x^2], x, x]] 0 ...
462 views

### Strange behaviour of Reduce for Mod[x,1]

For every integer $x$ the equation Mod[x, 1] == 0 holds. While Simplify[Mod[x, 1] == 0, Element[x,Integers]] gives ...
449 views

Bug still present in version 10 under Windows. In a recent posting, Belisarius solved a problem related to the display of arrows on the x and y axes by setting ...
377 views

### FindInstance returns Indeterminate in version 9, but not in 8

Bug introduced in 9.0 and fixed in 10.0.0 Here is a trivial system of equations in three unknowns for which FindInstance obtains a solution: ...
650 views

### How would I return a random Mathematica command?

I'm doing some metaprogramming. How would I make a Mathematica function that returns a random Mathematica command? Is there a list of command names that I could use ...
463 views

### Why do NumberForm and Round apparently use different tie-breaking methods?

When rounding numbers (for example, rounding a real number to the nearest integer), the "round to nearest" rule is usually used. For example, 1.4 is rounded down to 1 and 1.6 is rounded up to 2. ...
777 views

### How do I “start a reference system”?

When I attempt to insert a citation or specify a database to use as a bibliography, I get a message that I need to "start" the "reference system" "manually": I have no idea what a references system ...
826 views

### Does $x>0$ imply that $x\in\mathbb{R}$?

Let’s assume I input Assuming[x > 0, expression] Is it assumed by Mathematica that $x$ is a real number? Or that the real part of $x$ is positive? Something ...
545 views

### Evaluation indicator for a notebook

I have a GUI with a number of TabView and other Manipulate controls. Sometimes clicking from one tab view to the other can take ...
2k views

### How do I find the degree of a multivariable polynomial automatically?

I have a very simple question which appears not to have already been answered on this forum. Is there built-in functionality that returns the degree of a multivariable polynomial? For example if the ...
577 views

### How to embed an image into a string?

Note: The bug described in the post is in Mathematica 9, and has been fixed in 10.0. The documentation for String contains the following statements: Strings ...
337 views

### ToNumberField won't recognize Root as an explicit algebraic number

Bug fixed in 10.0.0 In Mathematica 9.0.1, it appears that ToNumberField will not always recognize a Root object as an ...
828 views

### Problems with “Test Connectivity” and the Pacletserver

I know there has been a similar questions to this already but the solution did not work for me so here again: I have internet connection and I can execute such commands like: ...
832 views

### Why can't I change the value of MaxRecursion in NIntegrate when integrating BesselJ?

Bug introduced in 8.0.4 or earlier and persists through 10.4. I am trying to evaluate this integral numerically $$\int_0^{\infty } J_0(q R) \tanh(q) \, \mathrm{d}q$$ for large values of $R$. ...
1k views

### Why is ListDensityPlot unable to plot datasets with extreme ranges

Consider the following dataset: data = Flatten[ Table[{x 10^-9, y 10^-9, x^2 + y^2},{x, -100, 100, 10}, {y, -100,100, 10}] , 1]; If I try to ...
284 views

### Evaluate selection in new window or new notebook?

Sometimes when you have long code you need to check some part of this code. the way I am using currently is to selected the part that I want and then copy it to new notebook and then evaluate it ...
138 views

### Strange result of Reduce and ForAll

In the question Can Mathematica tell me if a polynomial has all real roots?, quite a few of interesting answers were given. I wanted to add another one, using quantors, and observed some strange ...
344 views

I have a ragged list ragged = {{a,b,c,d,e},{x,y,z}} that I would like to trim (on the right) to be rectangular. The desired result is ...
325 views

### Return partial result when MemoryConstrained aborts NDSolve

I use NDSolve to solve a large set (~400) of coupled ODEs. Sometimes, the memory (~4GB) gets filled up, and my computer becomes impossible to work with, because it ...
451 views

### Predictive interface eats my Esc key

After updating to version 9, I found the predict interface very helpful except there is a small problem always annoying me: Consider this: I have a list ...
2k views

### Conditional options in Plot

I was hoping to incorporate an If function into a Plot option, as in ...
566 views

### How can I highlight a moving bar in an animation of a bar chart?

I wrote the following code, but I don't know how to highlight the moving bar. ...
2k views

### Estimating the full width half maximum of a peak

I have a dataset of which I'm attempting to determine the full width at half maximum. A picture of the data is given below, and the dataset itself can be found here (pastebin). Now, this set has a ...
459 views

4k views

### Plot columns of table if some condition is fulfilled

I have a table with data, for example MT = {{1, 80.3, 1, 4, 68}, {2, 80.5, 1, 5.5, 102}, {3, 80.0, 0, 4.2, 78}, {4, 80.4, 0, 3, 17}, {5, 80.2, 1, 5, 180}}; ...