# Download package to simplify complex conjugation

I want to use Needs to download the QuickReIm package to simplify the complex conjugation, but I keep getting errors:

here is the Command:

Needs["QuickReIm"]


and here are the errors:

Get::noopen: Cannot open QuickReIm.
Needs::nocont: Context QuickReIm was not created when Needs was evaluated.

Do you know the reason? Where can I find different packages and their uses?

• Is it in your Applications folder? Dec 28 '19 at 1:13
• Needs does not download anything (please check its documentation). What it does is it loads a package, provided that that package is installed. Downloading the package and installing it is something you need to do yourself before the package can be used. "QuickReIm" is not a standard package. If you have a question about it, you should clarify where one can get this package. Dec 28 '19 at 11:20

Not sure about the package you're referring to, but after a quick search I found Quantum Methods with Mathematica (result 5) which gives the source code for their version of the QuickReIm package as

BeginPackage["QuickReIm"]
Begin["Private"]
protected = Unprotect[Re, Im, Conjugate]
Conjugate[expr_] := expr /. Complex[x_, y_] :> x - I y
Re[expr_] := Expand[(expr + Conjugate[expr])/2]
Im[expr_] := Expand[(expr - Conjugate[expr])/(2 I)]
Protect[Release[protected]]
End[]
EndPackage[]


And then Needs["QuickReIm"]` evaluates without error.