9.5.2 Greatest hits from previous weeks

9.5.2.1 What does "Tag Integer is Protected" message mean?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=6738

(Newbie question) 
 
For every function I define I get this message: 
When I close and reopen Mathematica, and re-enter the function definition, I don't get the message anymore. What does it mean? 
[warning-messages]
 

asked by stevenvh https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=1450 Score of 15

answered by J. M.'s persistent exhaustion https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 Score of 16

9.5.2.2 1 Plot, 2 Scale/Axis

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=627

I would like to plot those two datasets on top of each other. But they have very different range on the $y$ axis. How can I have two different axis? 
 
I found the following on the help menu but quite ... 
[plotting] [customization]
 

asked by 500 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=172 Score of 158

answered by ArgentoSapiens https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=92 Score of 160

9.5.2.3 How can I transpose x and y axis on a Plot?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=18655

This question has appeared in various forms online, but I have not yet seen a complete answer, so I am posting it here. 
 
More specifically, suppose I have a function 
 
... 
[plotting] [graphics]
 

asked by merlin2011 https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=5619 Score of 18

answered by kglr https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=125 Score of 25

9.5.2.4 How do I draw a pair of buttocks?

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=66538

I'm trying to develop a function which 3D plot would have a buttocks like shape. 
 
Several days of searching the web and a dozen my of own attempts to solve the issue have brought nothing but two ... 
[plotting] [graphics3d] [generative-art]
 

asked by Simpleton Jack https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=22399 Score of 353

answered by mikuszefski https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=7608 Score of 554

9.5.2.5 How to find the position of elements in a list satisfying criteria

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=180

Say I have a list  x={2,4,6,8,10}  and I want to find out the positions of the elements that are greater than 7. 
 
... 
[list-manipulation]
 

asked by PeterR https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=140 Score of 72

answered by J. M.'s persistent exhaustion https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=50 Score of 71

9.5.2.6 Conversion of Sine to Cosine

https://mathematica.stackexchange.com/landing/r/digest?cta=question&id=67521

I'm solving equations with many Cosines and Sines. 
And I want to convert all the Sines to Cosines using trigonometric formulas such as cos(x)=sin(x+pi/2). 
How can I do this? 
[trigonometry] [conversion]
 

asked by YongCheol Kwon https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=23041 Score of 5

answered by Sjoerd C. de Vries https://mathematica.stackexchange.com/landing/r/digest?cta=user&id=57 Score of 2

9.5.2.7 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