Solve the equation `z^3=i`

Explanation

`z^3=i=cos((3pi)/2)+isin((3pi)/2)`
`=cos(2kpi+pi/2)+isin (2kpi+pi/2)`
`=cos(pi(4k+1))/2 +sin(pi(4k+1))/2`
`:.z=[cos((4k+1))/2+isin((4k+1)pi)/2]^(1/3)
`=cos((4k+1)pi)/6+isin((4k+1)pi)/6`
`"where" k=0,1,2.`