9.25.2 Greatest hits from previous weeks

9.25.2.1 Calculate the 2D Fourier transform of an Image
9.25.2.2 Where can I find examples of good Mathematica programming practice?
9.25.2.3 Make a scatter plot from two lists
9.25.2.4 Cutting bagels into linked halves
9.25.2.5 What is the equation to plot a vertical line?
9.25.2.6 Plotting a Phase Portrait
9.25.2.7 Plotting the frequency spectrum of a data series using Fourier
9.25.2.1 Calculate the 2D Fourier transform of an Image

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=29203

I am new to Mathematica, and using version 8.0. 
 
I would like to calculate the 2D Fourier Transform of an  Image  with Mathematica and plot the magnitude and phase ... 
[image-processing] [image] [fourier-analysis]
 
asked by user8727 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=8727 Score of 20
answered by Nasser https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=70 Score of 37
9.25.2.2 Where can I find examples of good Mathematica programming practice?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=18

I consider myself a pretty good Mathematica programmer, but I'm always looking out for ways to either improve my way of doing things in Mathematica, or to see if there's something nifty that I haven't ... 
[reference-request] [programming]
 
asked by J. M.'s lack of A.I. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 Score of 594
answered by faysou https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=66 Score of 521
9.25.2.3 Make a scatter plot from two lists

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=21884

I have two lists of values 
 
 xx = {0.1, 0.3, 0.35, 0.57, 0.88, 1.0} 
yy = {1.2, 3.5, 4.5, 7.8, 9.0, 12.2} 
 
 
I want to make a scatter plot (list plot) with xx as x ... 
[plotting]
 
asked by JACKY88 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2403 Score of 28
answered by Eric Thewalt https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=6313 Score of 43
9.25.2.4 Cutting bagels into linked halves

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=7545

I recently came across this video: Mathematically correct breakfast, which shows how a bagel can be neatly sliced into two identical linked halves. 
I'd like to try this with Mathematica. Here's a ... 
[graphics] [graphics3d]
 
asked by rm -rf https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5 Score of 63
answered by Heike https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=46 Score of 77
9.25.2.5 What is the equation to plot a vertical line?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=59476

Please help. Trying to find area between three curves,  e^-x, x = 2, y = 1 . Can't find out how to plot  x = 2 . Don't want to use <... 
[plotting] [calculus-and-analysis]
 
asked by Cory https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=19717 Score of 7
answered by Basheer Algohi https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=13548 Score of 13
9.25.2.6 Plotting a Phase Portrait

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=14160

I'm trying to plot a phase portrait for the differential equation 
$$x'' - (1 - x^2) x' + x = 0.5 \cos(1.1 t)\,.$$ 
The primes are derivatives with respect to $t$. I've reduced this second order ODE to ... 
[plotting] [differential-equations]
 
asked by covertbob https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=4528 Score of 45
answered by David Slater https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1746 Score of 41
9.25.2.7 Plotting the frequency spectrum of a data series using Fourier

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=18082

 testData = Table[N@Sin[500 x], {x, 0, 100}]; 
ListLinePlot[Abs[Fourier[testData]], PlotRange -> Full] 
 
 
Gives me 
Which I do not expect because the Fourier ... 
[fourier-analysis]
 
asked by C. E. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=731 Score of 14
answered by KennyColnago https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=3246 Score of 16