4.43.1 Top new questions this week

4.43.1.1 Automatic edX Pdf Handout creator

https://mathematica.stackexchange.com/questions/159065/automatic-edx-pdf-handout-creator

 
I am trying to make an automatic handout creator for my courses on edX. 
It took me a long time to do it... 
 
%%%%%%%%%%%%%%%%%%%%% 
\cprotect\subsubsection{\verb||} 
\url{If you don't know edX:https://www.edx.org/} 
 
\begin{TEXTWinline} 
 
I wrote a program that adds to each slide  ...
 

- asked by totyped (14 votes), answered by M. Stern (4 votes)

4.43.1.2 The area of a unit disk is $2\pi$? (NIntegrate over a numerical region)

https://mathematica.stackexchange.com/questions/159194/the-area-of-a-unit-disk-is-2-pi-nintegrate-over-a-numerical-region

 
EDIT: The example below concerns the construction of a numerical region from a general boolean-valued function.  The question of how to properly construct such a region has been answered below (by M.  ...
 

- asked by Will.Mo (13 votes), answered by m_goldberg (12 votes)

4.43.1.3 How many Capitals are closer to me than my own?

https://mathematica.stackexchange.com/questions/159041/how-many-capitals-are-closer-to-me-than-my-own

 
A recent question in chat about "When you are in Aachen, Germany, five other countries capitals are closer than Berlin." triggered me to try to write something to find the cities automatically for  ...
 

- asked by pH13 - Yet another Philipp (9 votes), answered by J. M. (4 votes)

4.43.1.4 How to SortBy Last and in Reverse order?

https://mathematica.stackexchange.com/questions/159295/how-to-sortby-last-and-in-reverse-order

 
I am looking at the two functions SortBy and ReverseSort. 
 
SortBy[{{1, 2, 3}, {2, 3, 1}, {3, 1, 2}, {2, 2}}, Last] 
 
 
 
 
{{2, 3, 1}, {2, 2}, {3, 1, 2}, {1, 2, 3}} 
 
 
 
How do I sort this by the  ...
 

- asked by Chen Stats Yu (7 votes), answered by J. M. (7 votes)

4.43.1.5 CatalanNumber[-1] formula on functions.wolfram.com unequals result from Mathematica

https://mathematica.stackexchange.com/questions/159143/catalannumber-1-formula-on-functions-wolfram-com-unequals-result-from-mathemat

 
The formula for CatalanNumber[-1] on this functions.wolfram.com page gives: 
 
-(1/2) 
 
 
whereas CatalanNumber[-1] directly evaluated gives? 
 
-1
 

- asked by axelclk (7 votes), answered by J. M. (8 votes)

4.43.1.6 DiscretizeGraphics issues with transformations

https://mathematica.stackexchange.com/questions/159035/discretizegraphics-issues-with-transformations

 
I noticed DiscretizeGraphics does not work correctly with transformed Graphics such as 
 
Graphics[Rotate[Rectangle[], 30ř]] 
 
 
 
 
Both using Rotate and GeometricTransformation together with  ...
 

- asked by Sascha (7 votes), answered by aardvark2012 (5 votes)

4.43.1.7 How to locate a stream line starting from a saddle point?

https://mathematica.stackexchange.com/questions/159093/how-to-locate-a-stream-line-starting-from-a-saddle-point

 
I read in a table of gradient vectors and plot using the ListStreamPlot. I want to locate and color the line that represents the "boundary" of the flux. A flux line that 1)starts from a saddle point  ...
 

- asked by Jun Liu 6votes