i^1=ii^2=-1i^3=-ii^4=1i^5=ii^6=-1i^7=-ii^8=1...i^n当n=4k(k=0,1,2,...)时i^n=1当n=4k+1时i^n=i当n=4k+2时i^n=-1当n=4k+3时i^n=-i63=4*15+3i^63=-i