# Is there any reason i is left in the denominator here?

1. Feb 19, 2016

### Zacarias Nason

I'm reading up on continuity equations and in particular how it relates to the probability current, and I noticed both in the Wikipedia page subsection for QM talking about continuity equations and in the main page for probability current, plenty of the formulas given have i in the denominator of the coefficient at the front; is there any reason the eqns are left this way rather than multiplying both sides by i^2 and then multiplying through by -1 so the LHS is still the same sign but i isn't in the denominator? Leaving the i as is is just sort of "bad voodoo" to me but functionally the same and I'm curious if there's any convention or if that's just some bias I've developed on my own.

2. Feb 19, 2016

### MisterX

It's one of those things students develop from drills but it is not followed by professionals. Imaginary i in the denominator is common in physics literature. Same goes for radicals / square roots.

3. Feb 19, 2016

Thank you!