Question

The nth term of a sequence is given by 2n² + 1.

Write down the first three terms of this sequence.

Answer 1

3, 9, 19

Explanation:

substitute n = 1, 2, 3 into the nth term formula

n = 1 : 2(1)² + 1 = 2(1) + 1 = 2 + 1 = 3

n = 2 : 2(2)² + 1 = 2(4) + 1 = 8 + 1 = 9

n = 3 : 2(3)² + 1 = 2(9) + 1 = 18 + 1 = 19

the first 3 terms are 3, 9, 19