Question

if the sum of the first n terms of an ap is given by sn=(3n2-n) find its nth term.... ​

Answer 1

Answer:

Sn = 3n2 – n S1 = 3

(1) 2 – 1 = 3 – 1 = 2 S2 = 3

(2) 2 – 2 = 12 – 2 = 10 a1 = 2 a2 = 10 – 2 = 8

(i) an = a + (n – 1) d = 2 + (n – 1) x 6 = 2 + 6n – 6 = 6n – 4

(ii) First term = 2

(iii) Common difference = 8 – 2 = 6