Question

The principle argument of the complex number $-1-\sqrt{3}i$ is

• A. π/3
• B. - π/3
• C. 2π/3
• D. - 2π/3

Answer 1

The correct option is D

- 2π/3

$-1-i\sqrt{3}=r(cos\theta +isin\theta )\Rightarrow cos\theta =\frac{-1}{2},sin\theta =\frac{-\sqrt{3}}{2}\Rightarrow \theta =\frac{-2\pi }{3}$