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NDA Math Complex Numbers
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© examsnet.com
Question : 22
Total: 66
A complex number is given by
z=
1
+
2
i
1
−
|
1
−
i
|
2
What is the modulus of z?
[NDA I 2019]
4
2
1
1
2
Validate
Solution:
(C)
Given complex number
z
=
1
+
2
i
1
−
(
1
−
i
)
2
⇒
z
=
1
+
2
i
1
−
(
1
−
1
−
2
i
)
=
1
+
2
i
1
+
2
i
=
1
⇒ z = 1 + 0 i
Clearly |z| = 1 and arg (z)=0
© examsnet.com
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