i^i=e^(iLni)=e^(ii[2kPi+Pi/2])=e^(-2k-1/2)Pi
cosi=[e^(ii)+e^(-ii)]/2=[e^(-1)+e]/2
Ln(-i)=ln|-i|+i[2kPi+arg(-i)]=i[2k-1/2]Pi
正好熟悉,供批评参考.