已知复数z=(a-1)+(a+1)i(a∈R,i为虚数单位)是纯虚数,则a=(  ) A.-1 B.1 C.±1 D.0

问题描述:

已知复数z=(a-1)+(a+1)i(a∈R,i为虚数单位)是纯虚数,则a=(  )
A. -1
B. 1
C. ±1
D. 0

∵复数z=(a-1)+(a+1)i(a∈R,i为虚数单位)是纯虚数,

a−1=0
a+1≠0

∴a=1.
故选B.