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In an A.P. the pth term is q and the (p + q)th term is 0. Then the qth term is ______. - Mathematics

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Question

In an A.P. the pth term is q and the (p + q)th term is 0. Then the qth term is ______.

Options

  • – p

  • p

  • p + q

  • p – q

MCQ
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Solution

In an A.P. the pth term is q and the (p + q)th term is 0. Then the qth term is p.

Explanation:

Let a, d be the first term and common difference respectively.

Therefore, Tp = a + (p – 1)d = q ......(1)

Tp+ q = a + (p + q – 1)d = 0  .....(2)

Subtracting (1), from (2) we get qd = – q

Substituting in (1) we get

a = q – (p – 1)(–1) = q + p – 1

Now Tq = a + (q – 1)d = q + p – 1 + (q – 1)(–1)

= q + p – 1 – q + 1

= p

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Chapter 9: Sequences and Series - Solved Examples [Page 159]

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NCERT Exemplar Mathematics [English] Class 11
Chapter 9 Sequences and Series
Solved Examples | Q 17 | Page 159

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