This is a small presentation designed around Number Patterns. The content would be appropriate for a learner in the 11th or 12th grade in a CAPS currciulum school.
5. Linear sequences
• An linear sequence is a sequence where consecutive terms are
calculated by adding a constant value (positive or negative) to
the previous term. We call this constant value the common
difference (𝑑).
• For example,
• 3 ; 0 ; −3 ; −6 ;−9 ;…
• This is an linear sequence because we add −3 to each term to
get the next term:
6.
7. Try this one out:
• Find the common difference and write down the next 3 terms of
the sequence.
• 2 ; 6 ; 10 ; 14 ; 18 ; 22 ; …
8.
9. 𝑇𝑛=𝑎+(𝑛−1)𝑑
• 𝑇𝑛 is the 𝑛th term;
• 𝑛 is the position of the term in the sequence;
• 𝑎 is the first term;
• 𝑑 is the common difference.
10. Quadratic sequence
• A quadratic sequence is a sequence of numbers in which the
second difference between any two consecutive terms is
constant.
• The general formula for the 𝑛th term of a quadratic sequence is:
𝑇𝑛=𝑎𝑛2+𝑏𝑛+𝑐
11. • It is important to note that the first differences of a quadratic
sequence form an arithmetic sequence. This sequence has a
common difference of 2𝑎 between consecutive terms. In other
words, a linear sequence results from taking the first differences
of a quadratic sequence.
12. Try this one out
• A quadratic pattern is given by 𝑇𝑛=𝑛2+𝑏𝑛+𝑐. Find the values
of 𝑏 and 𝑐 if the sequence starts with the following terms:
−1 ; 2; 7 ; 14 ;…
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16. Additional Activities/ Reading
• Further reading, listening or viewing activities related to this
topic are available on the following web links:
• https://www.youtube.com/watch?v=UuceRRQGk8E
• (Linear sequences – nth term)
• https://www.youtube.com/watch?v=FfCq7bGAFoY
• (Quadratic sequences – nth term)