Convert z=−3iz = -3iz=−3i to polar form r(cosθ+isinθ)r(\cos\theta + i\sin\theta)r(cosθ+isinθ).
3(cos(π/2)+isin(π/2))3(\cos(\pi/2) + i\sin(\pi/2))3(cos(π/2)+isin(π/2))
3(cos(3π/2)+isin(3π/2))3(\cos(3\pi/2) + i\sin(3\pi/2))3(cos(3π/2)+isin(3π/2))
3(cos(0)+isin(0))3(\cos(0) + i\sin(0))3(cos(0)+isin(0))
3(cos(π)+isin(π))3(\cos(\pi) + i\sin(\pi))3(cos(π)+isin(π))