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If the sum of n terms of an AP be 3n^2+n and its common difference is 6, then its first term is? |
Answer» Thanks for replying quickly Given that Sum to n terms of an AP is3n² + nGiven common difference is 6,If suppose a is the first term of A.P and \'d\' is thecommon difference, the Sum to n terms of an A.P isgiven by Sn = (n/2)*[2a + (n - 1)d]Given Sn = 3n² + nIf we substitute n = 1 , in Sn we get Sum to 1 tems of an A.Pwhich is equivalent to first term of A.P itself,So, 1st term of A,P = S₁ = 3.1² + 1= 3 + 1= 4.Hence,\xa0first term of an A.P is 4. |
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