# All Questions

68 views

### RowReduce doesn't work for this matrix?

I have this matrix A={{0,1,1,w},{1,0,1,x},{-1,0,1,y},{0,1,1,z}} where w, x, y, z are arbitrary constants. This matrix should be row reduced to the form ...
85 views

### Exposing .csv via Wolfram Cloud API

I'm sure there's a better way to accomplish this, but my goal is to generate a .csv file from a running notebook, and have it accessible by API. In the main program, I'm exporting the data like so: ...
78 views

### RegionPlot Difficulty

This code: Plot3D[ArcTan[Tan[y/x]], {x, -1, 2}, {y, -2, 1}, RegionFunction -> Function[{x, y}, 1 <= x^2 + y^2 <= 4 && y <= x]] Give this ...
162 views

### Image shaking when Manipulate with slider

How to prevent the Graphics3D object in following code from shaking when continuously changing the phi parameter? ...
143 views

### How to handle Indeterminate TimeConstrain

I have to use Timeconstrained[aux] first for avoid some bigs calculation that dont need and it use a lot of time of calculate, so i can't do this. ...
122 views

### Tough Calculation, novice mathematica user

I have an equation, that I've been calling $b_N(x)$ that satisfies the following identity: $$-Nb_N(x)^2=(x-N)b_N(x)+xb_N'(x)$$ where $b_N'(x)$ is the first derivative. I take the derivative then of ...
102 views

322 views

### Backslide of Limit

A friend of mine showed me this example: Limit[Sum[Sin[Pi*k/n]/(n + 1/k), {k, 1, n}], n -> Infinity] This sample calculates well in v8.0.4: but not in ...
31 views

### How to make Expand work right in a function definition?

This works just fine: Derivative[n_, 1][g][x_, v_] := D[g[x, v], {x, n + 2}]/2 + D[D[g[x, v], x]^2/2, {x, n}]; h = Expand[D[g[x, v], {v, 3}]] I would like to ...
195 views

### Parentheses for negative integers

Trying to standard create prime factors presentation, but can't seem to remove the parentheses: ...
149 views

### Why Abs[Infinity] is an element of the real numbers

Element[Abs[Infinity], Complexes] returns False, that's right. But ...
149 views

### Compare two shifted signals

I have one set of original data (signal A) and a second set of derived data (signal B) which was computed from A by position rotation (circular shift). Here are the data for the signals (A and B): ...
138 views

### How can I number the section titles automatically in Mathematica?

When I write a document in Mathematica, I do not like to number the section title myself, because I usually add or delete a section from time to time. Is there a way that Mathematica can number the ...
103 views

### Unequal behaviour of FindRoot to two similar functions

Unfortunately, I have some difficulties to plot a function. Here is my code: ...
483 views

### Get 2d corner coordinates / layout using edge detection

I'm new to Mathematica but I found an interesting usage of it: I'm programming a 2D game, with a top-view, where I'd like to have the edge coordinates of the walls. EdgeDetection delivers me quite a ...
96 views

### symbolic integration of product of hankel function and trignometric function

I want to perform the following integration. my function is : r*cos(r)hankel(0,kr) i want to integrate from 0->pi , and want to get the expression in terms of k. I used this command ...
44 views

### Should this be equal to Gamma function or not?

I define the following function: Nat2[s_] := InverseFourierTransform[FourierTransform[1/t, t, w] (-I w)^(s - 1), w, x]/Cos[Pi (s - 1)] /. x -> 1 I expected ...