12.3.2 Greatest hits from previous weeks

12.3.2.1 How to ask Mathematica to imitate Andy Warhol's pop-art painting?
12.3.2.2 Finding unit tangent, normal, and binormal vectors for a given r(t)
12.3.2.3 Is there a syntax for single-line comments for notebooks?
12.3.2.4 Calculating the normalization constant for a wavefunction
12.3.2.5 Creating a table/Matrix during a For loop
12.3.2.6 Elegant operations on matrix rows and columns
12.3.2.7 Placing text within a plot
12.3.2.1 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 69
12.3.2.2 Finding unit tangent, normal, and binormal vectors for a given r(t)

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=18598

For my Calc III class, I need to find $T(t), N(t)$, and $B(t)$ for $t=1, 2$, and $-1$, given $r(t)=\{t,t^2,t^3\}$. 
 
I've got Mathematica, but I've never used it before and I'm not sure how to coerce ... 
[equation-solving] [calculus-and-analysis] [geometry] [vector-calculus] [homework]
 
asked by a98 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5605 Score of 33
answered by Artes https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=184 Score of 48
12.3.2.3 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 Score of 87
answered by Szabolcs https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=12 Score of 90
12.3.2.4 Calculating the normalization constant for a wavefunction

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=99248

How can I compute the normalization constant for a quantum mechanics wave-function, like $\Psi(x) = N \exp(-\lambda x^2/2)$ by using Mathematica? (The normalization constant is $N$). 
[physics]
 
asked by infiniteNOP https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=35524 Score of 2
answered by Jason B. https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=9490 Score of 5
12.3.2.5 Creating a table/Matrix during a For loop

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=2930

I have a  For  loop (with  i  as a counter), which calculates different values ( y1 , ... 
[matrix]
 
asked by Solarboy https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=727 Score of 12
answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 Score of 16
12.3.2.6 Elegant operations on matrix rows and columns

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=3069

Question 
 
The Mathematica tutorial has a section 'Basic Matrix Operations', describing operations like transpose, inverse and determinant. These operations all work on entire matrices. I am missing a ... 
[matrix] [list-manipulation] [faq]
 
asked by sjdh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=515 Score of 208
answered by Mr.Wizard https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=121 Score of 70
12.3.2.7 Placing text within a plot

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=71776

I want to place text within a plot. The text is always centered relative to the coordinates. How can I left-align or right-align the text relative to the coordinates? For example: 
 
... 
[plotting] [graphics] [text]
 
asked by Anthony Mannucci https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=24733 Score of 29
answered by m_goldberg https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=3066 Score of 14