Mathematics for IGCSE & O level - Sequences (Section 1 - No. 10)
Which of the following sequences could be defined by a quadratic formula?
5, 10, 15, 20...
1, 3, 6, 10...
2, 4, 8, 16...
3, 6, 9, 12...
Explication
A quadratic sequence has a constant second difference.