How is $i^3$ = $\sqrt{-i}$. I new to complex numbers.So please don’t mind.
We know $i^2$ = -1.
Then $i^3$ is written as $= -i$
Then does it’s steps of writing follow  this:
$-1^2$= $i^3$= 1
So in terms i = It says in my book
= -  $\sqrt{-i}$.
How did we get this ?
I have done calculation mistake while writing this question.I have now answered this question.
$i^3$ =   $\sqrt{-1}$. *  $\sqrt{-1}$.*  $\sqrt{-1}$.
Therefore it equals = -1 *  $\sqrt{-1}$.
Or we can write it also using the property he listed in his question.
$i^2$ * i = -i.
Remember:When a and b both are negative and are multiplied.
Therefore , it equals - $\sqrt{ab}$.
For the OP.
$i = \sqrt{-1~}$ so $i^2 = -1$ and $i^3 = i^2 \cdot i = -1 \cdot \sqrt{-1~} = -\sqrt{-1~}$
Hope This helps!