Sequences
Overview
A sequence is an ordered list of numbers that follows a rule. You meet sequences everywhere in mathematics: the multiples of 7, the square numbers, the Fibonacci numbers. On the Edexcel IGCSE, you need to continue a sequence from a given rule, spot the pattern in a sequence of integers, and write an expression for the nth term of an arithmetic (linear) sequence.
This lesson starts with term-to-term rules (where each term depends on the one before) and position-to-term rules (where each term depends on its position number). You will then learn how to find the nth-term formula for arithmetic sequences by inspection and, at Higher tier, use the formal notation \(a + (n - 1)d\) and the sum formula for arithmetic series.
Objectives
- Generate terms of a sequence using term-to-term and position-to-term definitions of the sequence
- Find subsequent terms of an integer sequence and the rule for generating it
- Use linear expressions to describe the nth term of arithmetic sequences
- [Higher] Understand and use common difference (d) and first term (a) in an arithmetic sequence
- [Higher] Know and use nth term = a + (n - 1)d
- [Higher] Find the sum of the first n terms of an arithmetic series (Sn)
Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Sequences. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- The nth term of a sequence is 3n + 5. What is the 10th term? A) 30 B) 35 C) 38 D) 40 Answer: B
- Which of these sequences is arithmetic? A) 1, 4, 9, 16, ... B) 2, 6, 18, 54, ... C) 5, 9, 13, 17, ... D) 1, 1, 2, 3, 5, ... Answer: C
- The first term of a sequence is 8 and the common difference is -3. What is the 4th term? A) 2 B) -1 C) 5 D) 20 Answer: B
- The nth term of a sequence is 5n - 2. Which term has the value 48? A) 8th B) 9th C) 10th D) 11th Answer: C
- A sequence starts 6, 10, 14, 18, ... What is the common difference? A) 2 B) 3 C) 4 D) 6 Answer: C
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
Available on the Green Bridge App
Download the Green Bridge CBT app on your phone or computer to access full lesson notes, practice questions, and more.
Recommended Books
Practice Mock Questions
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