Write the nth term of an A.P. the sum of whose n terms is Sn.

1.	Write the nth term of an A.P. the sum of whose n terms is Sn.
Answer» First term = a Sum up to first term = a Last term (n^th term) = a_n Sum up to n terms = S_n Second last term = a_n–1 Sum up to (n–1)^th term = s_n–1 Therefore, a_n = S_n–S_n–1

Answer»

First term = a

Sum up to first term = a

Last term (n^th term) = a_n

Sum up to n terms = S_n

Second last term = a_n–1

Sum up to (n–1)^th term = s_n–1

Therefore, a_n = S_n–S_n–1

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