(n+i)^4=((n+i)^2)^2=(n^2+2ni-1)^2=(n-1)^2-4n^2+2(n^2-1)*2ni
2(n^2-1)*2ni为实数
2(n^2-1)*2n为实数
2(n^2-1)*2n=0
n=0或n^2-1=0
n=0或n=±1
共3个