Sequences & Series (AQA A-Level Mathematics): Flashcards

A list of numbers

The $n$th term of a sequence

Constant difference between consecutive terms (arithmetic)

Constant factor between consecutive terms (geometric)

Sum of the terms of a sequence

$S_n = \frac{n}{2}(2a + (n-1)d)$

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

$S = \frac{a}{1-r}$ when $|r| < 1$

Infinite series approaching a finite value

Sum terms $a_i$ from $i=1$ to $n$