Question

6. If the sum of first n terms of an A.P. is
Sn = 3n2 + 2n, find the nth term of the A.P.
(3)​

Answer 1

Answer:

Sn=3n2+2n

Sn-1=3 (n-1)2+2 (n-1)

=3 (n2+1-2n)+2n-2

=3n2+3-6n+2n-2

= 3n2-4n+1

therefore an=Sn-Sn-1

=3n2+2n-(3n2-4n+1)

=3n2+2n-3n2+4n-1

=6n-1

Answer 2

Answer:

6n-1

Step-by-step explanation:

put d value n=1,2,..u to get first term,common difference.

or simply solve by Tn =Sn-Sn-1.