复数z=4-i1+i的共辗复数的虚部为（）A.-52iB.-52C.52iD.52

Question

复数z=

(4-i)/(1+i)的共辗复数的虚部为（　　）

A. -

(5)/(2)i

B. -

(5)/(2)

C.

(5)/(2)i

D.

(5)/(2)

Answer 1

∵z=(4-i)/(1+i)=((4-i)(1-i))/((1+i)(1-i))=(3-5i)/(2)=(3)/(2)-(5)/(2)i，
∴

.

z

=(3)/(2)+(5)/(2)i．
∴复数z=(4-i)/(1+i)的共轭复数的虚部为(5)/(2)．
故选：D．