Intermediate Algebra 2e

# Key Terms

### Key Terms

annuity
An annuity is an investment that is a sequence of equal periodic deposits.
arithmetic sequence
An arithmetic sequence is a sequence where the difference between consecutive terms is constant.
common difference
The difference between consecutive terms in an arithmetic sequence, $an−an−1,an−an−1,$ is d, the common difference, for n greater than or equal to two.
common ratio
The ratio between consecutive terms in a geometric sequence, $anan−1,anan−1,$ is r, the common ratio, where n is greater than or equal to two.
finite sequence
A sequence with a domain that is limited to a finite number of counting numbers.
general term of a sequence
The general term of the sequence is the formula for writing the nth term of the sequence. The nth term of the sequence, $an,an,$ is the term in the nth position where n is a value in the domain.
geometric sequence
A geometric sequence is a sequence where the ratio between consecutive terms is always the same
infinite geometric series
An infinite geometric series is an infinite sum infinite geometric sequence.
infinite sequence
A sequence whose domain is all counting numbers and there is an infinite number of counting numbers.
partial sum
When we add a finite number of terms of a sequence, we call the sum a partial sum.
sequence
A sequence is a function whose domain is the counting numbers.