Use the formula z=a+bi=|z|(cosθ+isinθ), with |z|=√(a²+b²), and tanθ=b/a
in this case, a=0, b=-3 so |z|=√0²+(-3)²)=3
tanθ=[tex] \frac{-3}{0} [/tex], notice the denominator is 0, undefined, so the value of θ=π/2
Substitute the values of θ=π/2 and |z|=3. into the formula, you'll get 3(cos([tex] \frac{ \pi }{2} [/tex])+isin([tex] \frac{ \pi }{2} [/tex]))
