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What is the sum of n terms of the series 2 + 8 + 18 + 32 + . ?

Options

  1. An ( n -1) 2
  2. B2 n ( n +1)
  3. Cn ( n +1) 2
  4. Dn ( n -1) 2

Correct answer

C. n ( n +1) 2

Step-by-step solution

aligned & 2 + 8 + 18 + 32 + . & = 2 +2 2 +3 2 +4 2 + . . & S _ n = 2 [1+2+3+4+ . n terms ] & = 2 n ( n +1) 2 = n ( n +1) 2 aligned

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