-216 = 216 e^(i*pi) = 6^3*e^(i*pi) =
6^3*e^(3 pi)= 6^3*e^(5 pi)
The cube roots of those number are is
6 e^(i*pi/3), 6 e^(i*pi) and
6 e(i*5pi/3)
The second of those numbers is -6. You can put the other two roots in complex form by using the identity
e^ix = cos x + i sin x
find the cube roots of -216
answer in polar form and complex
1 answer
1 answer