Sum of first n terms is 3n2 + n. Find the 22nd term.
Sum of first n terms is 3n2 + n. Find the 22nd term.
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a22 = S22 - S22-1
a22 = 3(22)²+22 - [3(21)²+21]
a22 = 1474 - 1344
a22 = 130
Hence the 22nd term of the AP is 130.
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