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imported>Chunbum Park m (geometric series) |
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A '''[[geometric series]]''' is a [[series (mathematics)|series]] associated with a [[geometric sequence]], | |||
i.e., the ratio (or quotient) ''q'' of two consecutive terms is the same for each pair. | |||
Thus, every geometric series has the form | |||
:<math> | |||
a + aq + aq^2 + aq^3 + \cdots | |||
</math> | |||
where the quotient (ratio) of the (''n''+1)th and the ''n''th term is | |||
:<math> | |||
\frac{a q^{n}}{aq^{n-1}} = q. | |||
</math> | |||
The sum of the first ''n'' terms of a geometric sequence is called the ''n''-th partial sum (of the series); its formula is given below (''S''<sub>''n''</sub>). | |||
An infinite geometric series (i.e., a series with an infinite number of terms) converges if and only if |''q''|<1, in which case its sum is <math> a \over 1-q </math>, where ''a'' is the first term of the series. | |||
In finance, since compound [[interest rate|interest]] generates a geometric sequence, | |||
regular payments together with compound interest lead to a geometric series. | |||
''[[ | ''[[Geometric series|.... (read more)]]'' | ||
Revision as of 09:45, 8 October 2011
A geometric series is a series associated with a geometric sequence, i.e., the ratio (or quotient) q of two consecutive terms is the same for each pair.
Thus, every geometric series has the form
where the quotient (ratio) of the (n+1)th and the nth term is
The sum of the first n terms of a geometric sequence is called the n-th partial sum (of the series); its formula is given below (Sn).
An infinite geometric series (i.e., a series with an infinite number of terms) converges if and only if |q|<1, in which case its sum is , where a is the first term of the series.
In finance, since compound interest generates a geometric sequence, regular payments together with compound interest lead to a geometric series.