设z=cost+isint --->|z|=1,1/z=z~=cost-isint 1)证：(z+1)/(z-1) =[(cost+1)+isint]/[(sint-1)+isint] ={2[cos(t/2)]^2+2isin(t/2)cos(t/2)}/{-2[sin(t/2)]^2+2isin(t/2)cos(t/2)} =2cos(t/2)/[-2isin(t/2)]*[cos(t/...