AlgebraKey Facts

Key Facts

Part of Quadratic SequencesGCSE Mathematics

This key facts covers Key Facts within Quadratic Sequences for GCSE Mathematics. Revise Quadratic Sequences in Algebra for GCSE Mathematics with 12 exam-style questions and 22 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 2 of 7 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.

Topic position

Section 2 of 7

Practice

12 questions

Recall

22 flashcards

Key Facts

Term Definition Example
Quadratic Sequence A sequence where the second differences are constant 2, 5, 10, 17, 26, 37...
First Differences Differences between consecutive terms 3, 5, 7, 9, 11...
Second Differences Differences between first differences 2, 2, 2, 2...
nth Term Formula an² + bn + c n² + 2n - 1
Coefficient 'a' Half of the second difference If 2nd diff = 4, then a = 2

Keep building this topic

Read this section alongside the surrounding pages in Quadratic Sequences. That gives you the full topic sequence instead of a single isolated revision point.

Practice Questions for Quadratic Sequences

Which of the following is a property of a quadratic sequence?

  • A. The first differences are constant
  • B. The second differences are constant
  • C. The terms increase by equal amounts each time
  • D. Every term is a perfect square
1 markfoundation

A student says: 'The sequence 3, 7, 13, 21, 31 is quadratic because the first differences increase.' Explain whether the student is correct and how to check properly.

2 marksstandard

Quick Recall Flashcards

What is a quadratic sequence?
A sequence where the second differences between consecutive terms are constant. Example: 2, 5, 10, 17, 26, ... First differences: 3, 5, 7, 9, ... Second differences: 2, 2, 2, ... (constant)
What are second differences?
The differences between the first differences. First differences: 4, 6, 8, 10 Second differences: 2, 2, 2 If second differences are constant, the sequence is quadratic.

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