Question

Which of the following is a third root of the given complex number? 64(cos(pi/7)+isin(pi/7)?

My choices are in the image below:

Answer 1

what is your choice?

Answer 2

Hint: Apply De Moivre theorem
\[z^n = r^n(cos~ n \theta+isin ~n\theta)\]

Answer 3

ok, let me try that. :)

Answer 4

My answer would be B. because 1/3 * 64 = 4 and 1/3 * pi/7 = pi/21.

Answer 5

Thank you! :)

Answer 6

good job