How do i solve this problem?

Question

Find the polar form of the complex number where the argument satisfies 0≤θ≤2π.

0+3i

oobleck · Accepted Answer

the real part is zero, so it's a pure imaginary: on the y-axis 0+3i = (3,π/2)

Shadow · Answer

Doh! I’m an idiot.

oobleck · Answer

of course, it could also be (-3,3π/2) ...