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If the sum of n terms of an A.P. be 3n2 + n and its common difference is 6, then its first term is - Mathematics

MCQ

If the sum of n terms of an A.P. be 3n2 + n and its common difference is 6, then its first term is

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  • 3

  • 1

  • 4

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Solution

In the given problem, the sum of n terms of an A.P. is given by the expression,

Sn = 3n2 + n

Here, we can find the first term by substituting n = 1 as sum of first term of the A.P. will be the same as the first term. So we get,

Sn = 3n2 + n

S1 = 3 (1)2 + (1)

     = 3 +1

      = 4

Therefore, the first term of this A.P is a = 4  .

  Is there an error in this question or solution?
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APPEARS IN

RD Sharma Class 10 Maths
Chapter 5 Arithmetic Progression
Q 3 | Page 57
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