Modelling with Sequences (Cambridge International AS Mathematics)

Modelling with Sequences & Series

How do I model with sequences and series?

• Many real-life situations can be modelled using progressions
• If a quantity is changing repeatedly by having a fixed amount added to or subtracted from it then the use of arithmetic progressions is appropriate

• If a quantity is changing repeatedly by a fixed percentage, or by being multiplied repeatedly by a fixed amount, then the use of geometric progressions is appropriate

Exam Hint

• Remember, an exam question won't always tell you to use progression methods, so you've got to be able to spot 'hidden' progression questions.
• To help you do this, be suspicious of questions about savings accounts, salaries, sales commissions, profits and the like – these are often progression questions in disguise!

Worked Example