Or,

                i * 1/i = 1
        =>  i * i * 1/i = i
        =>         -1/i = i
        =>          1/i = -i


>
> If i=sqrt(-1) then i^2=-1 so by substitution,
>
>         1/i     = -(-1)/i
>
>                 = -i^2/i
>
>                 = -i
>
> So 1/sqrt(-1) <> sqrt(-1) but 1/sqrt(-1) = -sqrt(-1)
>

/*****************************************/
/* Matt Calder, Dept. of Statistics, CSU */
/* http://www.stat.colostate.edu/~calder */
/*****************************************/