(1)已知z1=5+10i,z2=3-4i,1z=1z1+1z2,求z.(2)已知(1+2i).z=4+3i,求z及z.z.-数学

题目简介

(1)已知z1=5+10i,z2=3-4i,1z=1z1+1z2,求z.(2)已知(1+2i).z=4+3i,求z及z.z.-数学

题目详情

(1)已知z1=5+10i,z2=3-4i,
1
z
=
1
z1
+
1
z2
,求z.
(2)已知(1+2i)
.
z
=4+3i,求z及
z
.
z
题型:解答题难度:中档来源:不详

答案

(1)∵class="stub"1
z1
=class="stub"1
5+10i
=class="stub"5-10i
(5+10i)(5-10i)
=class="stub"1-2i
25
class="stub"1
z2
=class="stub"1
3-4i
=class="stub"3+4i
25

class="stub"1
z1
+class="stub"1
z2
=class="stub"4+2i
25

故z=class="stub"25
4+2i
=
25(4-2i)
20
=5-class="stub"5
2
i.
(2)∵
.
z
=class="stub"4+3i
1+2i
=class="stub"10-5i
5
=2-i,
∴z=2+i,class="stub"z
.
z
=class="stub"2+i
2-i
=class="stub"3+4i
5

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