Sigma notation

Learn sigma notation for Grade 12 CAPS Maths: what Σ means, how to use sigma notation, the formula and a worked NSC-style example.

Shorthand Σ for the sum of a series.

Definition

Sigma notation uses the Greek letter Σ to write a sum compactly. The lower value is the starting index and the upper value is the ending index; the number of terms is (upper − lower + 1).

Worked example

Σ (from n = 1 to 5) 2n = 2 + 4 + 6 + 8 + 10 = 30.

Where it appears in the exam

Paper 1 asks you to expand a sigma expression, calculate its value, write a series in sigma notation, or solve for the upper limit.

Step-by-step method

  1. Find the number of terms: upper − lower + 1.
  2. Substitute the lower value to get the first term.
  3. Substitute the next values to see whether the series is arithmetic or geometric.
  4. Use the matching sum formula.

Common mistake

Counting the terms as upper − lower and losing one term.

Related sequences terms

Frequently asked questions

What does sigma notation mean in Grade 12 Maths?

Sigma notation uses the Greek letter Σ to write a sum compactly. The lower value is the starting index and the upper value is the ending index; the number of terms is (upper − lower + 1).

Which NSC paper tests sigma notation?

Sigma notation belongs to the Sequences section of CAPS Grade 12 Mathematics, which is examined in Paper 1.

How do I practise questions involving sigma notation?

Snap a question that uses sigma notation into the Snap&Learn AI solver, or work through the sequences topic guide and NSC past papers.

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