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Sum of n terms of any A.P is n^2+2n . Find the first term and common difference
Dear student 1st term can be written as T1 = S1 = 1 + 2 = 3 nowS2 = T1 + T2 = 8 hence T2 = 8- 3 = 5 hence common difference = T2 – T1 = 5- 3 = 2
Sn = n² + 2n;S(n-1) = (n-1)² + (n-1) = n2-nTn = Sn - S(n-1) = 3nThus, d = Tn - T(n - 1), where Tn-1 = 3n-1Hence, d = 3n-3n+1=1 and first term isTn=a+(n-1)1 3n =a+n-1 a=2n+1please approve
Sn = n² + 2n;
S(n-1) = (n-1)² + (n-1) = n2-n
Tn = Sn - S(n-1) = 3n
Thus, d = Tn - T(n - 1), where Tn-1 = 3n-1
Hence, d = 3n-3n+1
=1 and first term isTn=a+(n-1)1
3n =a+n-1
a=2n+1
please approve
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