Modelling with Trigonometric Functions (Edexcel IAL Maths)

Spec point — 2.3

Modelling with trigonometric functions

How do I model with trigonometric functions?

• Various real-life situations can be modelled using trigonometric functions

• You need to be able to interpret the equations used in the model

• If you need to identify maximum or minimum values of a formula, remember the bounds of the sin and cos functions:

  • -1 ≤ sin x ≤ 1
  • -1 ≤ cos x ≤ 1

• You may need to simplify trigonometric expressions to make the behaviour of an equation clearer

• You may also need to discuss the period of an equation

  • The period is often indicated by T
  • For a periodic function in x like sin or cos, the period is how much x has to change by for the function to go through one complete cycle

• For functions of the form cos (qx+ r) or sin (qx + r) the period T is:

Exam Hint

• The variable in these questions is often t for time.
• Read the question carefully to make sure you know what you are being asked to solve.

Worked Example