Hack request: rational numbers

[Erik Max Francis]

chaoweilun at my-deja.com wrote:

> Sorry,BTW,could anyone tell me,why the letter "j" is used
> to represent complex numbers, but not "i"?

i is commonly used by mathematics, j is commonly used by engineers. 
Physicists tend to use i more frequently than j.

-- 
 Erik Max Francis / max at alcyone.com / http://www.alcyone.com/max/
 __ San Jose, CA, US / 37 20 N 121 53 W / ICQ16063900 / &tSftDotIotE
/  \ I go out with actresses because I'm not apt to marry one.
\__/ Henry Kissinger
    Maths reference / http://www.alcyone.com/max/reference/maths/
 A mathematics reference.