Sequences – Key Terms & Definitions
Essential sequences vocabulary for IGCSE Mathematics (0580). Each term includes a clear definition and example to help you understand and remember key concepts.
sequence
CoreOrdered list of numbers following a pattern
Example
2, 5, 8, 11, ...
term
CoreIndividual number in a sequence
Example
The 3rd term is 8
nth term
CoreFormula giving any term from its position
Example
nth = 3n - 1
linear sequence
CoreConstant difference between terms
Example
2, 5, 8, 11 has difference 3
quadratic sequence
ExtendedSecond differences are constant
Example
1, 4, 9, 16 (second diff = 2)
geometric sequence
ExtendedConstant ratio between terms
Example
2, 6, 18, 54 (ratio = 3)
common difference
CoreConstant added each time in linear sequence
Example
d = 3 in 2, 5, 8, 11
common ratio
ExtendedConstant multiplied each time in geometric
Example
r = 3 in 2, 6, 18, 54
rule
CoreDescription of how sequence works
Example
Add 3 each time
generate
CoreProduce terms from a rule
Example
nth = 2n gives 2, 4, 6, 8
position-to-term
CoreRule converting position to value
Example
Position 4 → term 11
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How many sequences terms do I need to know for IGCSE?
This glossary covers 11 key sequences terms. Focus on understanding definitions and being able to use each term in context during exams.
Are these terms for Core or Extended?
Terms are labelled as Core or Extended. Core students should focus on Core-labelled terms, while Extended students need to know all terms.
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