Reference to this formula X = cube root of R

[jaus tail]

Hi,
Sorry for this weird question. My computer crashed and also the notes in it. I had a book wherein I'd written all the formulae. There is one formula in notes of Power System.
X = cube root of R.

I remember there was a website that even had its derivation, but I don't have the bookmarks anymore.
It's something to do with Power System, maybe minimum losses or maximum power factor.

Can someone please help me as to regarding what question is the answer:
X = cube root of R.

 

[berkeman]

I used Google to search on your words X = cube root of R, and then refined the search by adding "in power systems". That showed me that you probably meant the square root of R and 3-phase power systems:

http://www.electricalpereview.com/square-root-three-3-electrical/

Does that look like what you remember?

 

[jaus tail]

No. I'd even downloaded a pdf from some website that said same formula. Thanks by the way.
I'll search again Tomorrow.