What is the argument of [tex]$-1+\sqrt{3}i$[/tex]?

A. [tex]30^{\circ}[/tex]
B. [tex]120^{\circ}[/tex]
C. [tex]60^{\circ}[/tex]
D. [tex]150^{\circ}[/tex]



Answer :

To determine the argument of the complex number [tex]\( -1 + \sqrt{3}i \)[/tex], we'll follow these steps:

1. Identify the components of the complex number:
- The real part [tex]\(a\)[/tex] is [tex]\(-1\)[/tex].
- The imaginary part [tex]\(b\)[/tex] is [tex]\(\sqrt{3}\)[/tex].

2. Calculate the argument [tex]\(\theta\)[/tex] using the arctangent function:

[tex]\[ \theta = \text{atan2}(b, a) \][/tex]

Here, [tex]\(\text{atan2}(b, a)\)[/tex] provides the angle [tex]\(\theta\)[/tex] in radians such that:

[tex]\[ \theta = \text{atan2}(\sqrt{3}, -1) \][/tex]

3. Convert the argument from radians to degrees:

[tex]\[ \theta \approx 1.0471975511965976 \text{ radians} \][/tex]

To convert this into degrees, we use the conversion factor [tex]\(\frac{180}{\pi}\)[/tex]:

[tex]\[ \theta_{\text{degrees}} = \theta \times \frac{180}{\pi} \approx 1.0471975511965976 \times \frac{180}{\pi} \approx 60^\circ \][/tex]

4. Round to the nearest integer degree if necessary:

[tex]\[ \theta_{\text{rounded degrees}} \approx 60^\circ \][/tex]

Therefore, the argument of the complex number [tex]\(-1 + \sqrt{3}i\)[/tex] is [tex]\(\boxed{60^\circ}\)[/tex].