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📐 Mathematics  ·  Sequences and Series  ·  JEE

Sum of first n odd numbers (1+3+5+...+(2n-1)) =

Answer: n².

  • A n
  • B n+1
  • C
  • D n(n+1)/2

Correct answer: C. n²

Explanation: Sum of first n odd numbers = n². For n=4: 1+3+5+7 = 16 = 4².

Each bar grows by the common difference d=3a1=2a2=5a3=8a4=11d=3

Bar heights for AP 2, 5, 8, 11 with the common difference d=3 marked between consecutive terms.

Concept context

Arithmetic progressions, geometric progressions, and sums

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