Find the first four terms of the sequence whose nth terms are given by

(iii) an = 2n2 - 6

Solution :

an = 2n2 - 6

n = 2

= 2(2)2 - 6

a2 = 2

an = 2n2 - 6

n = 1

= 2(1)2 - 6

a1 = -4

Hence the four terms are -4, 2, 12, 26.