Quadratic Sequences (Junior Cert Mathematics): Quizzes

Second differences are constant

$3, 5, 7, 9$

$2, 2, 2$

$T_n = an^2 + bn + c$

$a$ is half the second difference

$a = 1$

$b + c = 3$

$b = 0$, $c = 3$

$T_n = n^2 + 3$

$T_3 = 12$