4.24.2 Greatest hits from previous weeks

4.24.2.1 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)

4.24.2.2 Entering numbers in Scientific Notation?

https://mathematica.stackexchange.com/questions/36792/entering-numbers-in-scientific-notation

 
I need to play with a lot of powers such as 10^-3. 1E-3 does not work for it. Is there any short form for it?
                                                                                  

                                                                                  
 

- asked by hhh (32 votes), answered by Rahul (43 votes)