我睇虛數位既powers(冪),有以下規律
i^1=i
i^2=-1
i^3=-i
i^4=1
i^5=i
i^6=-1
...
之就話個規律係 i^n=i^n(mod4)
http://upload.wikimedia.org/math/3/0/d/30da315472384d87125afafbf0627d00.png
姐係n-n is divisible by 4??
咁可唔可以寫做n=n(mod4) ?? (咦…又好似唔係好岩喎…)
同埋中間點解係=而唔係≡???