# All Questions

508 views

### Evaluating FindRoot at different starting points on a grid

I'm trying to evaluate the roots of a complex function at different starting points on a grid using Do[Do[FindRoot[g[z], {z, j + k*I}], {j, 10}], {k, 10}]. However, ...
210 views

### Issue with ListConvolve

I am a new Mathematica user, learning the intricacies of functional programming. I have issues withe applying a function over a moving list. My function seems to work and give correct results but it ...
853 views

### How make f[{x,y}] evaluate as f[x,y]? [duplicate]

I frequently encounter the situation where I have a function of two real variables defined, e.g.: f[x_, y_] := 9 - x^2 - y^2 But then I need to feed into ...
142 views

### Detect Standalone CDF vs Browser Plugin environment [duplicate]

Recently, Wolfram informed me that there's no way to have a Print button in a CDF running within a plugin environment since the plugin does not interact with the operating system. If you have a way to ...
203 views

### How can I add a background to a stylesheet?

In version 9 we can set the background to an image, however I'd like to save this into a stylesheet that can be installed.
1k views

### How to change coordinates of integration?

Is there some built-in routine, some easier method to change variables of integration, without/before solving the integral? Say I have ...
133 views

### Plotting an array of data onto a sphere [duplicate]

See the link to plot at the bottom of this post, it is a function of the spherical coordinates theta and phi. It is generated by MatrixPlot of an Array of data. I would like to plot this onto a sphere ...
729 views

482 views

### How to get the determinant and inverse of a large sparse symmetric matrix?

For example, the following is a $12\times 12$ symmetric matrix. Det and Inverse take too much time and don't even work on my ...
3k views

### How can I detect a rectangular region of interest in a picture?

Here is a downsampled input image I converted to greyscale. To select the rectangular region of interest we first preform preprocessing: ...
461 views

### How can I draw temperature 3D plot?

I want to draw temperature 3D plot based on given data points {{x1,y1,z1},{x2,y2,z2},...}. Here z coordinate is temperature.Am going to Show the temperature z in corresponding {x,y} coordinate. In my ...
239 views

### Integrate[(1 + x/n)^n*Exp[-x], {x, 0, Infinity}]

I evaluated Integrate[(1 + x/n)^n*Exp[-x], {x, 0, Infinity}] . thinking the answer should be approximately $\sqrt{\pi n/2}$. Mathematica gave me ...
164 views

### Why is FindRoot initial value far from the specified one?

I am trying to numerically find the root of a function that looks a bit like: 1/x - (SchurDecomposition[A[x]][[2]])[[1]], where ...
686 views

### Check Google PageRank for a given URL

Does anyone know how to write a Mathematica function that returns the Google PageRank of a given URL? I found a tutorial for achieving this in a bash script here, but I have no idea how to port this ...
182 views

### How to construct pairs in a list?

I have an expression like this, input = x[1] x[2]^3 x[5]^2; Fist step, we can get a list from the input expression, ...
113 views

### FindFit and Integration errors

First off, appologies for what may sound like a newbie question, as I am very new to using Mathematica. I am trying to find a way to get Mathematica to give me an expression that would describe the ...
494 views

### Efficient code for solve this equation

We have $a*b*c=-1$, $\frac{a^2}{c}+\frac{b}{c^2}=1$, $a^2 b+a c^2+b^2 c=t$ What's the value of $a^5 c+a b^5+b c^5$? I tried ...
160 views

### An issue regarding Eigenvalues function [closed]

Can anybody please kindly explain to me why the members of the output vector produced by the following example are not equal to zero? ...
303 views

### How to reject or repulse some points in a 3D cloud of particles?

I'm having an issue with a 3D distribution of points. The distribution is really nicely looking in Mathematica, but it is used in an OpenGL astronomy program (Celestia) to generate a nebula, with ...
142 views

I'm having some trouble with identical code giving different answers. On a fresh kernel (MM 9.0.0.0, Windows 64-bit), running the same code, copy-paste, gives two different answers: ...
608 views

### Running a Numerical Simulation on a System of Differential Equations with unique initial conditions

I have a system of differential equations as follows: ...