The sum of the first n terms of an A.P. is 4n2 + 2n. Find the nth term of this A.P.
Sn = 4n2 + 2n
First term, a = 4(1)2 + 2(1)
= 4 + 2 = 6
Sum of first two terms, S2 = 4(2)2 + 2(2)
a + a + d = 16 + 4
6 + 6 + d = 20
d = 8
Now the nth term, an = a + (n – 1) d
= 6 + (n – 1) 8
= 6 + 8n – 8
= 8n - 2