Sequences and Series

Vocabulary

arithmetic sequence

sequence that has a constant difference between consecutive terms

arithmetic series

sum of terms in an arithmetic sequence

common difference

number that is the difference between consecutive terms in an arithmetic sequence. The difference between a term and the previous term is always the same value.

common ratio

number that is the ratio between consecutive terms in a geometric sequence. The ratio between a term and the previous term is always the same value.

convergent series

series in which the sequence of partial sums approaches a fixed number

divergent series

series in which the sequence of partial sums does not approach a fixed number

explicit rule

rule used to find any term in a sequence directly, given its position in the sequence

Fibonacci sequence

sequence of numbers in which each term is found by adding the two previous terms. The first several terms of the sequence are 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, ….

finite sequence

sequence with a limited number of terms

finite series

sum of the terms in a finite sequence

geometric sequence

sequence that has a constant ratio between consecutive terms

geometric series

sum of terms in a geometric sequence

infinite sequence

sequence that continues without end

infinite series

sum of terms in an infinite sequence

partial sum

sum of a specified number of terms in a sequence

recursive rule

rule that tells how to find any term in a sequence by using the previous term

sequence

ordered list of numbers

series

sum of terms of a sequence

summation notation

abbreviated way of writing a sum that uses the Greek letter sigma. n=19an\sum_{n=1}^{9}a_n is read as "the sum of aa sub nn as nn goes from 1 to 9."

term of a sequence

number in a sequence