It is known that the sum of the first n terms of the sequence is Sn = n2-3n + 1, (1) find the general term formula, (2) try to judge whether the sequence an is an arithmetic sequence

It is known that the sum of the first n terms of the sequence is Sn = n2-3n + 1, (1) find the general term formula, (2) try to judge whether the sequence an is an arithmetic sequence

(1)
When n = 1, A1 = S1 = 1-3 + 1 = - 1
When n ≥ 2, an = n & # 178; - 3N + 1 - [(n-1) & # 178; - 3 (n-1) + 1] = 2n-4
The above formula does not hold when n = 1
∴an={-1 ,(n=1)
{2n-4 ,(n≥2)
(2)
When n ≥ 2, an-a (n-1) = 2
But A2 = 0, A1 = - 1, a2-a1 = 1 ≠ 2
The {an} sequence does not conform to the definition of arithmetic sequence, not arithmetic sequence