i n = { i , if n mod 4 = 1 − 1 , if n mod 4 = 2 − i , if n mod 4 = 3 1 , if n mod 4 = 0 {\displaystyle i^{n}={\begin{cases}i,&{\mbox{if }}n{\bmod {4}}=1\\-1,&{\mbox{if }}n{\bmod {4}}=2\\-i,&{\mbox{if }}n{\bmod {4}}=3\\1,&{\mbox{if }}n{\bmod {4}}=0\\\end{cases}}}
i n = { i , if the remainder of n / 4 = 1 − 1 , if the remainder of n / 4 = 2 − i , if the remainder of n / 4 = 3 1 , if the remainder of n / 4 = 0 {\displaystyle i^{n}={\begin{cases}i,&{\mbox{if the remainder of }}n/4=1\\-1,&{\mbox{if the remainder of }}n/4=2\\-i,&{\mbox{if the remainder of }}n/4=3\\1,&{\mbox{if the remainder of }}n/4=0\\\end{cases}}}