Find the modulus of each of the following complex numbers and hence express each of them in polar form: –2

Let Z = -2 = r(cosθ + isinθ)


Now, separating real and complex part, we get


-2 = rcosθ………. eq.1


0 = rsinθ …………eq.2


Squaring and adding eq.1 and eq.2, we get


4 = r2


Since r is always a positive no.,therefore,


r = 2,


hence its modulus is 2.


now, dividing eq.2 by eq.1 , we get,



Tanθ = 0


Since cosθ = -1, sinθ = 0 and tanθ = 0. Therefore the lies in second quadrant.


Tanθ = 0, therefore θ = π


Representing the complex no. in its polar form will be


Z = 2(cosπ + isinπ)


1