In an ap , the sum of first n terms is 3n2/2 + 13n/2 . Find the 25th\xa0\xa0term.

In an ap , the sum of first n terms is 3n2/2 + 13n/2 . Find the 25th\x

1.	In an ap , the sum of first n terms is 3n2/2 + 13n/2 . Find the 25th\xa0\xa0term.
Answer» Sn\xa0= 3n2/2 + 13n/2S1\xa0= a = 3/2 + 13/2 = 8S2\xa0= a + a2\xa0= 12/2 + 26/2 = 19a2\xa0= 19 - 8 = 11Then,. d = 11 -8 = 3Now, a25\xa0= a +(25 - 1)d= 8 + 24 × 3= 80The 25th term is 80