What is the principal argument of z = -5i in radians?
Answer and explanation
Correct answer: D. -pi/2
- Step 1: z = -5i = 0 - 5i. In the complex plane, this point is (0, -5). Step 2. This lies on the negative vertical axis, which has angle -pi/2 radians. Answer: -pi/2. Why not the others: Principal arguments are defined in the interval (-pi, pi].
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