Square root of -i

[The Bad Astronomer]

Hmmm...

sqrt(a * b) = sqrt(a) * sqrt(b)

so

sqrt(-i) = sqrt(-1) * sqrt(i) = i sqrt(i)

 

[pgwenthold]

Hmmm...

sqrt(a * b) = sqrt(a) * sqrt(b)

so

sqrt(-i) = sqrt(-1) * sqrt(i) = i sqrt(i)

So now all you need is the square root of i and you have it.