Hey guys i was working through this question and when i cheked my answers i realised there was an extra bit to do to get the final answer but i dont know wt im supposed to do:
Q) Express (-1 + sqrt3i) in modulus-argument form. Evaluate (-1 + sqrt3i)^8,
expressing your answer in a + ib form.
I got z= 2cis 2pi/ 3 for mod -arg form but when i evaluate it I can get to:
2^8 cis 16pi/3
but then the answers tell me tht the answer above is equal to 2^8 cis 4pi/3???
And that the final answer in a+ ib form is : -128 - 128sqrt3i .
What i want to know is how do i go from 2^8 cis 16pi/3 ==> -128 - 128 sqrt3i??