Find the rth term of an AP, the sum of whose first n terms is `(3n^(2) +2n)`

Answer

`T_(r)=(6r-1)`

Explanation

`S_(n)=3n^(2)+2nRightarrow S_(n-1) = 3 (n-1)^(2) + 2(n-1) Rightarrow s_(n-1) = 3n^(2) -4n +1`
` T_(n) = ( S_(n)-S_(n-1)) = (3n^(2) +2n) -(3n^(2)+(4n+1)= (6n-1) Rightarrow T_(r)= (6r-1)`