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If the n^(t h) term of an A.P. is (2n+1)...

If the `n^(t h)` term of an A.P. is `(2n+1),` find the sum of first `n` terms of the A.P.

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For AP, `a_n = a+ (n-1)d = 2n-1`
`a_1 = 2-1 = 1`
`a_2 = 4-1 = 3`
Common difference ,` d = 3-1 = 2`
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