Write 2i in polar form.

Let, z = 2i

Let 0 = rcosθ and 2 = rsinθ

By squaring and adding, we get

(0)² + (2)² = (rcosθ)² + (rsinθ)²

⇒ 0+4 = r²(cos²θ + sin²θ)

⇒4 = r²

⇒ r = 2

∴ cosθ= 0 and sinθ=1

Since, θ lies in first quadrant, we have

Thus, the required polar form is