I know that ${1\over i} = -i$ where $i = \sqrt{-1}$. Can anyone figure out the mistake in the following lines?

**1/i = 1/squareroot(-1) = squareroot(1)/squareroot(-1) = squareroot(1/(-1)) = squareroot(-1/1) = squareroot(-1) = i**

${1\over i}={1\over \sqrt{-1}}={\sqrt{1}\over \sqrt{-1}}=\sqrt{1\over -1}=\sqrt{-1\over 1}=\sqrt{-1}=i$

Which is a contradiction? I tried hard, but I am not able to figure out what's wrong with the above equations. Thank You.