Find the nth term of the sequence 3, 6, 10, 15, 21.....

  • A \(\frac{n(n - 1)}{2}\)
  • B \(\frac{n(n + 1)}{2}\)
  • C \(\frac{(n + 1)(n + 2)}{2}\)
  • D n(2n + 1)
jamb 1994mathematics

The correct answer is C. \(\frac{(n + 1)(n + 2)}{2}\)

\(\frac{(n + 1)(n + 2)}{2}\)

If n = 1, the expression becomes 3

n = 2, the expression becomes 6

n = 4, the expression becomes 15

n = 5, the expression becomes 21

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