Christoph Hormann <chr### [at] gmxde> wrote:
> Just to make it clear: n^2=permittivity*permeability is not a
> definition, it's just a furmula n is supposed to comply with (and there
> is no unique solution for n).  n = sqrt(permittivity*permeability) would
> be a definition but it would not allow negative n (sqrt(x) is positive
> or imaginary for any non-complex x).

n*n = x, but also (-n)*(-n) = x. The positive n is the principal value of
the root, not the only valid value.

Post a reply to this message