Given the first n terms of {an} and Sn = an2 + BN (a is not equal to 0), find the general term formula of {an} and prove that the sequence is arithmetic sequence

Given the first n terms of {an} and Sn = an2 + BN (a is not equal to 0), find the general term formula of {an} and prove that the sequence is arithmetic sequence


(1) It is proved that the arithmetic sequence is an = a + B-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 B-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 B-2 A-2 A-2 A-2 A-2 A-2 A-2 B-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 B-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 A-2 a-