问题
填空题
若复数(a-i)(1+i)(i是虚数单位,a∈R)是纯虚数,则a=______.
答案
∵(a-i)(1+i)=a+ai-i-i2=a+1+(a-1)i,
∴a+1=0,
则a=-1.
故答案为:-1.
若复数(a-i)(1+i)(i是虚数单位,a∈R)是纯虚数,则a=______.
∵(a-i)(1+i)=a+ai-i-i2=a+1+(a-1)i,
∴a+1=0,
则a=-1.
故答案为:-1.