Loading…
Loading…
GCSE Mathematics · key term
The differences between consecutive first differences.
Used by AQA and OCR
Specification A24, A25 · Paper 1, Paper 2, Paper 3
Revise: Quadratic and Surd SequencesYou do not need to know that rule before recognising the sequence: for terms at consecutive integer positions, constant second differences are the key sign. This happens because the first differences of a quadratic expression form a linear sequence.
Specification 6.06a · Paper 1 (Foundation), Paper 2 (Foundation), Paper 3 (Foundation), Paper 4 (Higher), Paper 5 (Higher), Paper 6 (Higher)
Write first differences directly beneath the original terms and second differences beneath those. A constant first difference means linear; a constant second difference means quadratic.
In a quadratic sequence, align the differences carefully. Five terms give four first differences and three second differences.
The coefficient of is half the constant second difference, not the whole second difference.
Create a free account to read GCSE Mathematics revision notes for your exam board and track your progress.
The changes between consecutive first differences. They are constant for a quadratic sequence.
In a quadratic sequence, the first differences change, but their differences—the second differences—are constant.