Question

设z的共轭复数是，若z+=4,z·=8,则等于

(A)i                       (B)－i                   (C)1                  (D) i

Answer 1

D设z=a+bi,则=a-bi(a,b∈R),

∵z+=4,z·=8,

∴a=2,a²+b²=8.∴b=±2.

当b=2时,=i,当b=-2时,=-i.

故选D.