# Copmlex Number

1. Apr 9, 2009

### latentcorpse

i've confused myself

$\frac{1}{i}=-i$ by multiplying by i/i

but then $(\frac{1}{i})^2=-1 \Rightarrow \frac{1}{i}= i,-i$
and clearly the positive root here doesn't make any sense???

2. Apr 9, 2009

### Focus

You are correct but you forgot to take the negative root of the left hand side.

3. Apr 9, 2009

### Pengwuino

Well you've somewhat answered your own question. You simply did pick the incorrect root as there are always 2 roots to a square root

$$$\begin{array}{l} 3 = 3 \\ 3^2 = 3^2 \\ 9 = 9 \\ \sqrt 9 = \sqrt 9 \\ 3 = - 3? \\ \end{array}$$$

for example.