e^[i(a+ib)]-e^[-i(a+ib)]=2isin(a+ib)；
2isin(a+ib)=e^[i(a+ib)]-e^[-i(a+ib)]=e^(-b+ia)-e^(b-ia)=[e^(-b)*(e^ia)]-[e^b*e^(-ia)]
=e*(-b)*(cosa+isina)-e^b*(cosa-isina)
=[e^(-b)-e^b]cosa+i[e^(-b)+e^b)]sina
∴ sin(a+ib)={[e^(-b)+e^b]sina}/2+{[e^b-e^(-b)]cosa}/2；