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Patterns & Sequences

Arithmetic, quadratic and geometric sequences, series, sigma notation, convergence and exam practice.

CAPS Aligned Grade 12 Focused Paper 1 Exam Revision
T_n = a + (n-1)d

Intro Video Lesson

Start here for the big picture before working through the notes, mastery bank and mastery test.

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Key Concepts

Master these ideas before attempting the mastery bank and test.

Arithmetic Sequence

Each term changes by a constant difference d. General term: T_n = a + (n - 1)d.

Geometric Sequence

Each term is multiplied by a constant ratio r. General term: T_n = ar^(n - 1).

Arithmetic Series

Sum of n terms: S_n = n/2[2a + (n - 1)d] or S_n = n/2(a + l).

Geometric Series

Sum of n terms: S_n = a(r^n - 1)/(r - 1). If |r| < 1, S_infinity = a/(1 - r).

Sigma Notation

Sigma notation is shorthand for a sum. Identify the general term and the range of values.

Core Formulas

Commit these to memory. They appear in almost every exam.

Arithmetic General Term
\[ T_n = a + (n-1)d \]
a = first term, d = common difference, n = term number.
Geometric General Term
\[ T_n = a \cdot r^{n-1} \]
a = first term, r = common ratio.
Sum to Infinity (|r| < 1)
\[ S_\infty = \frac{a}{1-r} \]
Only valid when the series converges, i.e., |r| < 1.

After This Topic You Will Be Able To

These are your learning targets for Patterns & Sequences.

Identify arithmetic vs. geometric sequences
Find any term using the general term formula
Calculate sums of finite series
Apply the sum to infinity formula
Interpret and evaluate sigma notation

Common Exam Mistakes

Avoid these errors. They cost marks every year.

Using n instead of (n - 1)

The formula is a + (n - 1)d, not a + nd. Off-by-one errors lose marks.

Applying S_infinity when |r| >= 1

The infinite sum formula only works if the series converges. Always check |r| < 1 first.

Confusing arithmetic and geometric

Check the pattern: constant difference (arithmetic) vs. constant ratio (geometric).

Topic Support Resources

Use these HTML resources in order: learn the notes, practise by level, then test yourself.

NOTES
Study Notes
Patterns & Sequences Summary Notes

Complete CAPS-aligned notes covering arithmetic, quadratic and geometric sequences, series, sigma notation, convergence and exam strategy.

Step 1 • Learn • HTML Notes
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BANK
Question Bank
Patterns & Sequences Mastery Bank

Vetted real paper questions grouped by cognitive level, with exact source references and memo-style answer routes.

Step 2 • Practise • Referenced
Open Mastery Bank
TEST
Self-Assessment
Patterns & Sequences Mastery Test

A 20-question interactive test with instant feedback, cognitive-level performance colours and a printable report.

Step 3 • Test Yourself • Auto Marked
Open Mastery Test
Recommended order: watch the intro video, read the notes, practise in the mastery bank, then complete the mastery test.

Frequently Asked Questions

Straight answers to common Grade 12 CAPS questions about Patterns and Sequences.

What are Patterns and Sequences in Grade 12 Maths?

Patterns and Sequences in Grade 12 CAPS covers arithmetic sequences, geometric sequences, series, and sigma notation. You learn how to identify patterns, find terms, and calculate sums.

How do I improve at sequence questions?

Start by deciding whether the pattern is arithmetic or geometric, then use the correct formula carefully. Regular practice helps you recognise the structure of questions much faster.

What mistakes should I avoid in Patterns and Sequences?

Common mistakes include mixing up arithmetic and geometric formulas, using the wrong term number, and confusing the nth term with the sum formula. Careless calculator input also causes errors.

How do Patterns and Sequences appear in CAPS exams?

CAPS exams usually test nth term, sum formulas, sigma notation, and practical pattern questions. These questions are common in Paper 1 and often connect to algebraic reasoning.

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