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Question 210004
JEE Mathematics · Easy

Sequences and Series: AP Sum Formula MCQ

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AP Sum FormulaEasyQuestion 210004

Question

The sum of first n terms of an AP with first term a and common difference d is:
  1. A
    n(a + l)/2
  2. B
    (n/2)(2a + (n−1)d)
  3. C
    Both A and B
    Correct
  4. D
    n × last term / 2

Correct answer

Both A and B

Explanation

Both formulas are equivalent: Sₙ = n(a+l)/2 where l = last term, and Sₙ = (n/2)[2a+(n−1)d]. Use whichever is convenient.

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