Question

the sum of the first n term of an AP is 2n^2+n. find nth term and common difference of the AP​

Answer 1

Step-by-step explanation:  Sn - Sn-1 = Tn

2n^2+2n - [ 2(n-1)^2 + 2n-2]

-> Tn = -5n+4 is the nth term

for common difference , put in values

for n=1 ,     -5+4 = -1

for n=2,       -10+4 = -6

therefore common diff =  -6 + 1 = -5