Sum of first n terms is 3n^2 + n. Find the 22nd Term.
Sum of first n terms is 3n2 + n. Find the 22nd Term.
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Sn = 3n2 + n
S22 = 3(22)2 + 22
S22 = 1452 + 22 ∴ S22 = 1474
S21 = 3(21)2 + 21
S21 = 1344
a22 = S22 - S21
∴ a22 = 1474 - 1344 ∴ a22 = 130
Hence, the 22nd term of A.P is 130
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