Quadratic Sequences (Leaving Cert Mathematics): Flashcards

nth term contains $n^2$ as highest power

$T_n = an^2 + bn + c$

Second differences are constant

Half the second difference

2

3

Half the second difference

Create a differences table

Check if second differences are constant

Use simultaneous equations

Substitute back to verify it works for original terms

If $a = 0$, sequence not quadratic