​ If the sum of the first n terms of an A.P. is given by S_n = n/2(3n+1) , then the firs term of the A.P. is ​

Question

If the sum of the first n terms of an A.P. is given by \(S_n = \frac{n}{2} (3n+1)\), then the firs term of the A.P. is 

(A) 2

(B) \(\frac{3}{2}\)

(C) 4

(D) \(\frac{5}{2}\)

Answer 1

Correct option is : (A) 2