The Slow Quiz

[A-Man]

Tricky question, I see.
Since √(-1) is i by definition. Polar form of that is [1, pi/2]. Taking the root using De Moivre's makes it either [1, pi/4] or [1, 5pi/4]. Changing to algebraic,
either: cos(pi/4) + sin(pi/4)i = 0.707 + 0.707i
or: cos(5pi/4) + sin(5pi/4)i = -0.707 - 0.707i

Sounds more like a Maths question, but I suppose saying its √(i) would've been enough?

EDIT: IT CAN ALSO BE WRITTEN AS e^(πi/4)

@v: You forgot the i :P