Summary (Grade 12 NSC Matric Mathematics): Quizzes

Constant difference between terms

$T_n = a + (n - 1)d$

A straight line

Second differences are constant

$r = \frac{T_n}{T_{n-1}}$

$T_n = ar^{n-1}$

The index variable

$S_n = \frac{n}{2}[a + l]$

$S_n = \frac{a(r^n - 1)}{r - 1}$

$-1 < r < 1$