(1+i)^i
=e^[iLn(1+i)]
=e^{i[ln|1+i|+iarg(1+i)+i2kπ]}
=e^{i[ln√2+iπ/4+i2kπ]}
=e^(iln√2-π/4-2kπ)
其主值=e^(iln√2-π/4)