Arithmetic Sequences (Leaving Cert Mathematics): Flashcards

A sequence where each term is found by adding the same fixed number to the previous term

$a$

$d$

$d = \text{any term} - \text{previous term}$

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

Sequence increases

Sequence decreases

The term you want to find

Position number of the term you want

Common difference added $(n-1)$ times, not $n$ times

Solve $T_n = \text{number}$; $n$ must be positive whole number

Substitute $n = 1, 2, 3$ to check original terms match