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NDA 2017
Exam
NDA
Year
2017
Subject
Mathematics
Chapter
Sequences and Series

NDA 2017 · Mathematics · Sequences and Series

If the sum of m terms of an AP is n and the sum of n terms is m ,...

If the sum of mm terms of an AP is nn and the sum of nn terms is m , then the sum of (m+n)(\mathrm{m}+\mathrm{n}) terms is

Options

  1. Amnm n
  2. Bm+nm+n
  3. C2(m+n)2(m+n)
  4. D−(m+n)-(m+n)

Correct answer

D. −(m+n)-(m+n)

Step-by-step solution

Given, Sm=n\mathrm{S}_{\mathrm{m}}=\mathrm{n} and Sn=m\mathrm{S}_{\mathrm{n}}=\mathrm{m} This is direct formula Sm+n=−(m+n)\mathrm{S}_{\mathrm{m}+\mathrm{n}}=-(\mathrm{m}+\mathrm{n})
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