7.32.2 Greatest hits from previous weeks

7.32.2.1 How can I plot the direction field for a differential equation?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=8841

I'd like to plot the graph of the direction field for a differential equation, to get a feel for it.  I'm a novice, right now, when it comes to plotting in Mathematica, so I'm hoping that someone can ... 
[plotting] [differential-equations]
 

asked by Matt Groff https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1735 34 votes

answered by Peter Breitfeld https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=307 27 votes

7.32.2.2 Get a "step-by-step" evaluation in Mathematica

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=148

Is it possible in Mathematica to get a step-by-step evaluation of some functions; that's to say, outputting not only the result but all the stages that have led to it? If so, how does one do it? 
 
... 
[evaluation] [interactive] [faq]
 

asked by Cydonia7 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=44 131 votes

answered by J. M.'s torpor https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 109 votes

7.32.2.3 Help find a bright object on Mars!

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=11819

In today's news, scientists found a bright object on one of Curiosity's photos (it's near the bottom of the picture below). It's a bit tricky to find - I actually spent quite some time staring at the ... 
[image-processing]
 

asked by Victor K. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1351 202 votes

answered by Niki Estner https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=242 263 votes

7.32.2.4 How to add a vertical line to a plot

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3561

In the plot below I would like to add two vertical lines at $x = \frac{\pi}{15} \pm \frac{1}{20}$. 
How can I do that? 
 
... 
[plotting]
 

asked by sjdh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=515 69 votes

answered by Ajasja https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=745 86 votes

7.32.2.5 Is there a syntax for single-line comments for notebooks?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=1496

I'm aware that I can use  (* ... *)  to comment out stuff in a notebook. Many languages have a syntax for single-line comments, such as 
... 
[syntax] [comment]
 

asked by Peeter Joot https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=10 77 votes

answered by Szabolcs https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12 78 votes

7.32.2.6 How can I plot a graph of an integral?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=78451

I want to plot the following function: 
 
$$\int \left(\frac{\Gamma (x+1)}{2}-\frac{\Gamma (x-1)}{2}\right) \, dx$$ 
[plotting]
 

asked by Anixx https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=651 5 votes

answered by k_v https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=24727 10 votes

7.32.2.7 Skip header lines on import

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=50718

When importing a data file what are the comment symbols for Mathematica? 
That is, given a file like this 
 
 blabla 
bulbul 
 
1 2 6 54 7 ... 
.. 
 
 
what symbol do I have ... 
[import] [text]
 

asked by MaxJ https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=14687 21 votes

answered by george2079 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=2079 18 votes