# All Questions

53 views

### Selecting from a list [duplicate]

OK, I know this must be a simple problem, but right now I'm just stuck and need some advice with this :). I have the following list: ...
42 views

### Specific formatting while exporting some data output into a file

I used the following code ...
198 views

### Strange result of an infinite sum

I have the following definition: o[a_] := Sum[ x^(2 k + 1) Product[(2 i + 1)^2 - a^2, {i, 0, k - 1}]/((2 k + 1)!), {k, 0, Infinity}] Now when I evaluate <...
311 views

### NdSolve problem :NDSolve::ndode: Input is not an ordinary differential equation

I am new to Mathematica. I am working on solving the following different equations numerically written in the code as below. Not so sure about the boundary values that depends on R (M(0)=0, n(1)=0) ...
548 views

### How can I draw a square root spiral? [duplicate]

I found this picture on the net. How can I reproduce it in Mathematica?
88 views

### How to reset the “front end” to a 200% default

I wish that when Mathematica is run the "front end" this default to 200%, and perhaps other things where you can not change, as there are directly in the menu. Thank You
552 views

### (NDSolve) Non-linear 2nd order ODE, regular singular point (looking for good methods for this problem)

I am solving this set of non-linear 2nd order ODE by NDSolve, $$r^2\frac{d^2f}{dr^2} = 2f(1-f)(1-2f)+\frac{r^2}{4}h^2(f-1)$$ $$\frac{d}{dr}\left[r^2\frac{dh}{dr} \right]=2h(1-f)^2+\lambda r^2(h^2-1)h$$...
70 views

### Enforcing WorkingPrecision in NIntegrate

I have a very complicated 2D integral that I need to calculate repeatedly, and I'm trying to speed it up a bit, since at the moment it's taking a couple of days to complete. One thing I've noticed is ...
113 views

### Visualize Space Pascal's triangle

Visualize Space Pascal's triangle I found this image on the web, I want to know how to draw with software. I try to search, found this. I have learned a mapping in the plane
41 views

### Different output, simple question [closed]

I found a slightly different output than what was expected in a book. DefSumMod[10] G={0,1,2,3,4,5,6,7,8,9} CircleGraph[G,Add[1]] Why is the tracing directed ...
785 views

### Nullclines and equilibrium point labels

I am trying to draw the vector field, nullclines, and equilibrium points for the system \begin{align*} x'&=2x-y+3(x^2-y^2)+2xy\\ y'&=x-3y-3(x^2-y^2)+3xy \end{align*} I have completed ...
281 views

### Converting between AbsoluteTime and Unix time

By trial and error, I've found that the following gives the current Unix time: AbsoluteTime[] - UPOCH where UPOCH can be defined in any of the following ways: <...
488 views

### Extracting road curves from an image

I have taken several gps readings while driving around town. ...
49 views

### How do I complete this function len for the length of a line segment?

I need to have len[{{x1,y1},{x2,y2}}] is Sqrt[(x2-x1)^2+(y2-y1)^2]. The beginning of the function will be defined as ...
61 views

### return multiple properties of financialdata

Sorry, very silly newbie question.. regarding FinancialData, how to return multiple specified properties. eg. if I want Open & Close properties , or perform an operation such as Open-Close ...
68 views

### Implicit region is not “valid” in ParamatricNDSolveValue function?

I am trying to solve a geometric problem with relation to my Schrodinger equation and its boundaries. Here is my code: ...
90 views

### Better control of vertex positions in GraphPlot?

I am trying to graphically visualize a sort of a transformation network. My program generates a list of vertices and edges and I want to turn that into a visually clear graph fulfilling a few ...
296 views

### Solving the symbolic quadratic equation ax2 + bx + c = 0 [closed]

I need to ask Mathematica to solve the symbolic quadratic equation ax2 + bx + c = 0. Does it give you the right answer?
155 views

### Surface Plot 3D of a strongly concave shape

I have a list of {x,y,z} points that all lie on the surface of an object (model output from COMSOL). I would like to generate a graphics object that reproduces the surface. Ideally, I would like ...
213 views

### Is there a bug in MatrixExp in Mathematica v10?

I'm trying to compute MatrixExp[-I t {{0, 1/2, 0, 0, 1/2}, {1/2, 0, 1/2, 0, 0}, {0, 1/2, 0, 1/2, 0}, {0, 0, 1/2, 0, 1/2}, {1/2, 0, 0, 1/2, 0}}] With ver 9 the ...
240 views

### Dynamic arrays and lists with compile (Append, Linked lists etc.)

I have a code that I need to compile. The code contains a loop in which I need to gather data into a list. The question is how to best gather data so that the code works inside Compile. The following ...
47 views

### Having trouble reading this output (pure functions) [duplicate]

I'm after decoupling some odes and trying to solve them using mathematica but my output is in terms of Functions and InverseFuntions and I'm afraid I have no idea how to translate the output into ...
131 views

### How to add a static JPEG into a Manipulate without slowing it down

I´m trying to add an image from a book into a Manipulate but it makes the Manipulate update very, very slowly. So much so that ...
123 views

### Problem with the BarChart3D function

I have a list of values {x,y,z} and I would like to create a 3D bar chart with axis x,y,z . ...
83 views

### The relative motion of the points about the common center of mass

There are 2 points with masses m1 and m2, their common center of mass   rC,r1 and r2 their radius vectors, r=Abs[r1-r2]. I built a trajectory of both material points, as well as their common center of ...
544 views

I am trying ...
120 views

### FunctionDomain doesn't work with If

When I call FunctionDomain for function defined by a formula with If, for example ...
170 views

### How to accelerate my code?

Given a 2D $M \times N$ matrix with non-negative values, I would like to find a path going from top to bottom such that the sum of the path is minimum. My function is defined as follow: ...
429 views

### Weierstrass function

I am trying to create plot of the Weierstrass function in Mathematica. I wonder if it's possible, when I define this function as ...
186 views

### How to use DSolve with vectors without decomposing into vector components?

Given a basic, two-dimensional ballistic trajectory problem, I can solve the equations of motion using DSolve (or NDSolve) by ...
75 views

### Are there any instruction(Mathematica-native) to draw an Arc in 3D? [duplicate]

I want to draw an arc in 3D. I viewed circles,ellipses and arcs in 2D with Circle[...] but when I want to draw and arc in 3D I can´t find any instruction for taht purpose. The question is: Are there ...
313 views

### How to make a binary function associative? (Or define an n-ary function?)

Suppose I have a simple function that I assign to an operator f[a_, b_] := a + b CirclePlus = f Then I want to write ...
192 views

### Is there a plot style for PolarPlot to look like matlab polar()?

The plot style of Matlab's polar function appears to be pretty conventional for antenna radiation patterns in the references I'm looking at (sometimes with tick markings that count +- from the ...
151 views

### Projectile motion with air friction

I need to find the x and y components of a projectile's position, its velocity at any evaluation point, time of flight, range, and maximum height. I have already made the code for a projectile ...
232 views

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368 views

### Row echelon form question

I am wondering if there is a Mathematica command that will put a matrix in row echelon form. That is, put $$\begin{bmatrix} 1 & 2 & 3\\ 2 & 3 & 4\\ -1 & 0 & 2 \end{bmatrix}$$...
77 views

### How to simplify an expression with a radical sign nesting in a radical sign

Is there a function can simplify an expression with a radical sign nesting in a radical sign in Mathematica? I use V9. RatDenmon is a function that can ...
126 views

### Random walk using Module [closed]

I want to create a random walk using Module. The walk start at {0, 0}. At every step, x ...
38 views

### Getting nicer values for eigensystems [closed]

I want to find the eigensystem of the matrix {{0.9, 0.5}, {0.1, 0.5}}. I tried Eigensystem[{{0.9, 0.5}, {0.1, 0.5}}] The ...
132 views

### How can I create a shortcut for a command in Mathematica?

I am using mathematica to write my physics homework, one thing that trouble me is that I need to enter lots of vectors. I usually type the name of the vector, "A" for example, and then hit "[Ctrl] 7" ...
128 views

### Block anti-diagonalize a square matrix?

In Mathematica there is a very convenient function called JordanDecomposition[]. It takes a square matrix A as an argument and ...
113 views

### Draw two curves and a surface

I'm trying to draw two curves and a surface, where one of the curves is to appear on the surface. Unfortunately the curves are drawn with very few points and appear extremely unclear. Is there a way ...
61 views

### Sort Unicode characters

Sorting ASCII phrases works fine: Sort[{"albatrob", "abo", "dict", "star", "mangel", "m"}] (*{"abo", "albatrob", "dict", "m", "mangel", "star"}*) But unless I'm ...
520 views

### Projectile motion in Mathematica using Euler's method [duplicate]

I need to write the equations of a ball in projectile motion (ignoring air friction) with an initial velocity of 40 m/s at an angle of 40° with respect to the horizontal. Specifically, I need to write:...
213 views

### Is there a way to detach/reattach the Frontend from a running Mathematica Kernel?

I perform long calculations on a fast remote machine running the Mathematica kernel, where I followed the very useful guide Remote Kernel Strategies to establish the connection. I wonder, however, if ...
44 views

### Writing a math formula to order results in a certain way [closed]

I am not very well educated in math and I have a math puzzle that I'm trying to solve. I have the following list and each object has 3 numbers. The first 2 numbers are better when they are as high as ...
541 views

### Find (longest) overlapping elements between two lists

I am trying to write a function f that returns the overlapped sublist where A ends with this sublist while ...
122 views

### TimeConstrained[Delete[Range[1],1]] causes kernel crash

Run these two samples of code here (AFTER SAVING YOUR CURRENT WORK): Do[ TimeConstrained[ While[True, Delete[{1}, 1]; ];, 0.1];, {100}] ...