复数z=1i-1(i为虚数单位)的模为()A.12B.22C.2D.2-高二数学

题目简介

复数z=1i-1(i为虚数单位)的模为()A.12B.22C.2D.2-高二数学

题目详情

复数z=
1
i-1
(i为虚数单位)的模为(  )
A.
1
2
B.
2
2
C.
2
D.2
题型:单选题难度:中档来源:不详

答案

z=class="stub"1
i-1
=class="stub"-1-i
(-1+i)(-1-i)
=class="stub"-1-i
2
=-class="stub"1
2
-class="stub"i
2

∴|z|=
(-class="stub"1
2
)2+(-class="stub"1
2
)2
=
2
2

故选:B.

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