Exponential Growth and Decay

This task introduces students to exponential growth and decay. It relates to compound interest for savings and depreciation of assets (e.g. cars).


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Mathematical Strands

Number and Measure, Financial Maths, Algebra and Graphs

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Prior Knowledge

An appreciation of percentages is required.

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Relevance to Core Maths qualifications

  • AQA
  • C&G
  • Eduqas
  • Pearson/ Edexcel
  • OCR

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Suggested approaches

Suitable for class discussion to introduce exponential growth and decay. The task would then be suitable for small group or individual work, according to students’ preferences.

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Resources/Documentation

In addition to this teacher guidance there are:

  • Information sheets on exponential growth and decay, with examples and questions posed relating to the shape of the graph (pdf)
  • Prepared templates for students to enter different y-values and sketch graphs
  • Repeated percentage change worksheet: compound interest (illustrated with ISAs), depreciation (illustrated with cars)
  • Geogebra worksheets

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Relevant digital technologies

Spreadsheet for modelling; graphing software/Geogebra/calculator

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Possible extensions

For related work, see the Core Maths Masters Subject Support, Strand: Graphs, Units 4 and 5. Possibly link with Cormathzadrine task for a further example of exponential decay.

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Acknowledgement

Developed by Tom Carpenter at Bishop Challoner Catholic College.