Sequences and Series

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A sequence is a pattern of numbers in order.

X 1, 3, 6, 10, 15, 21..........


Y 1, 3, 5, 7, 9, 11, 13,.......


Z 1, 3, 9, 27, 81, 243........


are three sequences.

Y is in arithmetic progression (AP) there is a common difference of 2.

Z is in geometric progression (GP) there is a common ratio of 3.

The nth term of an AP can be written as un=a+(n-1)d where a is the first term and d is the common difference.

The nth term of a GP can be written as un=ar^(n-1) where a is the first term and r is the common ratio.

A series is when a sequence of numbers is added.



www.mymaths.co.uk

No IB here but go to A level and find sections in Core 1 and Core 2.

http://en.wikipedia.org/wiki/Category:Sequences_and_series

This is the wikipedia site, it can get very technical very quickly.

http://www.mathsisfun.com/algebra/sequences-series.html

This site is quite a basic introduction to sequences and series, but might help for revision or if you missed a lesson.
Sequences_Worksheet.pdf