设z是虚数,w=z+(1/z)是实数,且-1u=(1-Z)/(1+Z)
问题描述：
设z是虚数,w=z+(1/z)是实数,且-1
u=(1-Z)/(1+Z)
答
令z=x+yi,则w=z+1/z=x+yi+(x-yi)/√(x²+y²)=[x+x/√(x²+y²)]+[y-y/√(x²+y²)]i
因为w是实数且-1