7.23.2 Greatest hits from previous weeks

7.23.2.1 How to find integer solutions?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=42359

Following is the equation: 
Need to solve for integer values of x,y when a,b lies between -1000 and 1000. 
Problem is to find the number of integer values of pair (x,y) that satisfy it. 
[equation-solving]
 

asked by Sahil Sareen https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12396 2 votes

answered by bill s https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1783 4 votes

7.23.2.2 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 55 votes

answered by Silvia https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=17 55 votes

7.23.2.3 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 38 votes

answered by David Slater https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1746 34 votes

7.23.2.4 Selecting every n-th element from a list

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=64003

I have a list: 
 
 data = {4, 5, 7, 8, 9, 5, 3, 2, 1, 2, 13, 12}; 
 
 
I want to take those elements in the list which are located at equal distances, say, every third ... 
[list-manipulation] [filtering]
 

asked by Suro https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=20003 37 votes

answered by Szabolcs https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12 34 votes

7.23.2.5 How can I plot implicit equations?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=34668

If you enter the following into Wolfram | Alpha, you get nice graphs: 
 
 graph 4 x^4 + y^2 = 2 
 
How do you do this in Mathmatica? I realize that these are not ... 
[plotting] [faq]
 

asked by Rollie https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=10174 40 votes

answered by Timothy Wofford https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9391 41 votes

7.23.2.6 Standard deck of 52 playing cards in curated data?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=16108

I am not sure how to find out what all is included as curated data. For example, are the individual images of each of the 52 cards in a standard deck of playing cards included? 
 
If not, is there a way ... 
[curated-data]
 

asked by JohnD https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1629 25 votes

answered by rm -rf https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5 23 votes

7.23.2.7 How to make a Spherical Cow?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=125043

Being a theoretical physicist, I always have a great respect for Spherical Cow. So I thought about making one myself. I am not sure how can I create (something considered to be the simplest!) this ... 
[geometry] [image3d]
                                                                                  

                                                                                  
 

asked by Sumit https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=8070 69 votes

answered by andre314 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5467 77 votes