9.11.2 Greatest hits from previous weeks

9.11.2.1 Is there an open source implementation of Mathematica-the-language?
9.11.2.2 How to plot an ellipse?
9.11.2.3 What is the difference between Reduce and Solve?
9.11.2.4 Why round to even integers?
9.11.2.5 How to perform a multi-peak fitting?
9.11.2.6 How do I plot $x^2+y^2=1$ in 3D?
9.11.2.7 How to ask Mathematica to imitate Andy Warhol's pop-art painting?
9.11.2.1 Is there an open source implementation of Mathematica-the-language?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=4454

I've seen questions before such as "What is the best open-source equivalent for Mathematica?", but that specific question (and that line of inquiry in general) cares more about the computer algebra ... 
[programming] [open-source]
 
asked by sblom https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=178 Score of 129
answered by Simon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=34 Score of 92
9.11.2.2 How to plot an ellipse?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=20100

I'm new to Mathematica, and I'm finding it difficult to plot an ellipse. 
I tried using 
 
 Plot[(x/5)^2 + (y/3)^2 == 1, {x, -5, 5}, {y, -3, 3}] 
 
 
but I'm getting ... 
[plotting]
 
asked by Sriram https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=6075 Score of 19
answered by Jens https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=245 Score of 33
9.11.2.3 What is the difference between Reduce and Solve?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=17127

 Solve  and  Reduce  both can be used for solving equations. 
 
Just by working with them, I know there are some differences between ... 
[equation-solving] [functions] [function-comparison]
 
asked by lachis83 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2371 Score of 109
answered by Artes https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=184 Score of 105
9.11.2.4 Why round to even integers?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=2116

According to the Mathematica help: 
Round rounds numbers of the form x.5 toward the nearest even integer. 
For example: 
 
 Round[{0.5, 1.5, 2.5, 3.5, 4.5}] 
 
 
gives 
... 
[numerics] [language-design]
 
asked by wxffles https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=427 Score of 86
answered by Per Alexandersson https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=488 Score of 53
9.11.2.5 How to perform a multi-peak fitting?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=26336

I am wondering how to implement the multi-peak detecting and fitting in Mathematica. Following is an example of fitting the data using three peaks (such that the data ~ peak1 + peak2 + peak3). 
The ... 
[fitting] [data] [peak-detection]
 
asked by Everett You https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1389 Score of 57
answered by Silvia https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=17 Score of 56
9.11.2.6 How do I plot $x^2+y^2=1$ in 3D?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=10710

How would I plot $x^2+y^2=1$ in 3D (it would form a cylinder)? Since there is no $z$ in the equation, I can't solve for it and use  Plot3D . Or can I just put the ... 
[plotting]
 
asked by diracdeltafunk https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2282 Score of 7
answered by Mark McClure https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=36 Score of 14
9.11.2.7 How to ask Mathematica to imitate Andy Warhol's pop-art painting?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=59132

I tried to ask Mathematica to imitate Andy Warhol, let it convert a Marilyn Monroe's portrait so that it looks like Warhol's world famous pop-art painting. However, the result shown below is far from ... 
[image-processing] [generative-art]
 
asked by Putterboy https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=16069 Score of 53
answered by Dr. belisarius https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=193 Score of 67