Question

The sum first n terms of an Ap is n2+n.find the nth term of the series

Answer 1

Answer:

an = 2(3-n)

Step-by-step explanation:

Sn = 2n +2

S1 = 2+2

= 4 = a1

S2 = 4+2

=6

S2 - a1 = a2

6-4 = 2 = a2

d = -2

an = a +(n-1)d

    = 4+ -2(n-1)

   = 4 -2n +2

   = 6-2n

   = 2(3-n)