# Find the principal argument of (–2i).

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 fourth quadrant, we have

Since, θ (-π ,π ] it is principal argument.

Rate this question :

How useful is this solution?
We strive to provide quality solutions. Please rate us to serve you better.
Related Videos
Polar & Euler Form of Complex Numbers on Argand Plane32 mins
Interactive Quiz Time - Polar & Euler Form of complex number58 mins
Interactive Quiz on Quadratic EquationsFREE Class
Modulus & Conjugate of Complex Number | Ready for a Quiz?48 mins
Practice session | Argument of complex numbersFREE Class
Special Quiz on Argument of complex numbersFREE Class
Polar & Euler Form of Complex Number on Argand Plane58 mins
Questions Based on Polar & Euler Form of Complex Number63 mins
Questions on Modulus & Conjugate of Complex Number62 mins
Interactive Quiz on Quadratic Equations-02FREE Class
Try our Mini CourseMaster Important Topics in 7 DaysLearn from IITians, NITians, Doctors & Academic Experts
Dedicated counsellor for each student
24X7 Doubt Resolution
Daily Report Card
Detailed Performance Evaluation
view all courses
RELATED QUESTIONS :

Write 2i in polar form.

RS Aggarwal - Mathematics