Question

把复数z的共轭复数记作 . z ，已知 (1+2i) . z =4+3i ，求z及 z . z ．

Answer 1

∵ (1+2i)

.

z =4+3i ，∴

.

z =

4+3i

1+2i =

(4+3i)(1-2i)

(1+2i)(1-2i) =

10-5i

5 =2-i，

∴z=2+i，∴

z

.

z =

2+i

2-i =

(2+i)(2+i)

(2-i)(2+i) =

4-1+4i

5 =

3

5 +

4

5 i．