4.36.2 Greatest hits from previous weeks

4.36.2.1 How to tell Mathematica that certain variables are real/imaginary, integer-valued, etc

https://mathematica.stackexchange.com/questions/66273/how-to-tell-mathematica-that-certain-variables-are-real-imaginary-integer-value

 
I'm trying to expedite some quantum mechanical calculations (expectation values etc.) by running them through Mathematica. When I say, for example, 
 
u[x_] := Sqrt[2/L] * Sin[Pi * n * x / L] 
 
 
and then  ...
 

- asked by Matthew Brunetti (17 votes), answered by SquareOne (11 votes)

4.36.2.2 How do I clear all user defined symbols?

https://mathematica.stackexchange.com/questions/850/how-do-i-clear-all-user-defined-symbols

 
Is there some way to do this other than going to Evaluation -> Quit kernel and firing a new one up?
                                                                                  

                                                                                  
 

- asked by niklasfi (55 votes), answered by Artes (54 votes)