7.21.2 Greatest hits from previous weeks

7.21.2.1 Plotting the Star of Bethlehem

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=236499

Christmas is around the corner! In preparation, consider the polynomial 
 f[x_,y_]:= 1/10 (4 - x^2 - 2 y^2)^2 + 1/2 (x^2 + y^2) 
 
and define $r=(f_x,f_y)$ using the ... 
[plotting] [equation-solving] [graphics] [performance-tuning] [visualization]
 

asked by JHT https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=44151 30 votes

answered by Roman https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=26598 22 votes

7.21.2.2 How to graph a sphere with cartesian equations?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=24169

I'm new to Mathematica and I need to ask how to graph a sphere, cylinder, etc.. using cartesian equations. 
 
For example in sphere's case $x^2+y^2+z^2=1$ 
 
I tried to use ... 
[plotting]
 

asked by German https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7145 8 votes

answered by Dr. belisarius https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=193 14 votes

7.21.2.3 Entering numbers in Scientific Notation?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=36792

I need to play with a lot of powers such as  10^-3 .  1E-3  does not work for it. Is there any short form for it? 
[number-representation]
 

asked by hhh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2000 65 votes

answered by Joe https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=44710 1 vote

7.21.2.4 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 14 votes

answered by KennyColnago https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=3246 16 votes

7.21.2.5 Is there something like DensityPlot3D to visualize atomic orbitals?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=32378

I'm visualizing some hydrogen like atomic orbitals.  For looking at plane slices of the probability density, the  DensityPlot  function works well, and with something ... 
[plotting] [physics] [chemistry]
 

asked by Peeter Joot https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=10 45 votes

answered by xslittlegrass https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1364 25 votes

7.21.2.6 Even Fibonacci numbers

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=37266

Today, I found the Euler Project. Problem #2 is 
 
Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be: 
... 
[number-theory] [project-euler]
 

asked by xyz https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9627 34 votes

answered by rcollyer https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=52 46 votes

7.21.2.7 Plotting Complex Quantity Functions

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3458

Trying to plot with complex quantities seems not to work properly in what I want to accomplish. I would like to know if there is a general rule/way of plotting when you have complex counterparts in ... 
[plotting] [complex] [faq]
 

asked by night owl https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=116 43 votes

answered by Artes https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=184 29 votes