Find all cube roots of the complex number. Leave answers in trigonometric form.
-$64 \mathrm { i }$
A) $1 , - 1 , - i$
B) $4 \operatorname { cis } 0 ^ { \circ } , 4 \operatorname { cis } 120 ^ { \circ } , 4 \operatorname { cis } 240 ^ { \circ }$
C) $4 \operatorname { cis } 30 ^ { \circ } , 4 \operatorname { cis } 150 ^ { \circ } , 4 \operatorname { cis } 270 ^ { \circ }$
D) $4 \operatorname { cis } 60 ^ { \circ } , 4 \operatorname { cis } 180 ^ { \circ } , 4 \operatorname { cis } 300 ^ { \circ }$

Question

Quizplus · Accepted Answer

The complex number $64i$ can be expressed in polar form as $64 \operatorname{cis} 90^\circ$. The cube roots will have a magnitude of $4$ and angles of $30^\circ$, $150^\circ$, and $270^\circ$.

Find All Cube Roots of the Complex Number 64i64 \mathrm { i }64i

Find All Cube Roots of the Complex Number $64 \mathrm { i }$