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If z = 32+i52+32-i52, then ______. - Mathematics

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Question

If z = `sqrt(3)/2 + i^5/2 + sqrt(3)/2 - i^5/2`, then ______.

Options

  • Re (z) = 0

  • Im (z) = 0

  • Re (z) > 0, Im (z) > 0

  • Re (z) > 0, Im (z) < 0

MCQ
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Solution

If z = `sqrt(3)/2 + i^5/2 + sqrt(3)/2 - i^5/2`, then Im (z) = 0.

Explanation:

On simplification, we get

z = `2  ""^5"C"_0  sqrt(3)^2/2 + ""^5"C"_2  sqrt(3)^3/2  i^2/2 + ""^5"C"_4  sqrt(3)/2  i^4/2`

Since i2 = –1 and i4 = 1

z will not contain any i and hence Im (z) = 0.

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Chapter 8: Binomial Theorem - Solved Examples [Page 142]

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NCERT Exemplar Mathematics [English] Class 11
Chapter 8 Binomial Theorem
Solved Examples | Q 22 | Page 142

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