Question

若{a/(1+i)+(1+i)/2}真含于R,则实数a等于

Answer 1

分母实化,虚部为0即可

a/(1+i)

=a(1-i)/(1+i)(1-i)

=(a-ai)/(1+1)

=(a/2)-(a/2)i

所以虚部=-a/2+1/2=0

a=1