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## Homework Statement

find all complex roots of z^8=81i

## Homework Equations

## The Attempt at a Solution

let the angle=x

z^8=r^8(cis8x)

we know

81i=81 (cis pi/2)

threfore

z^8=81(cos pi/2 + i sin (pi/2) )

8x= pi/2 + 2kpi

x = pi/16 + kpi/4 kEz

therefore

if k=1 z=sqrt3 (cis pi/16)

i go through this solutiosn...and should end up getting a result angle of pi/2 in one of them..becuse on of the roots is 1...so there i must be wrong..help