AQA A Level Maths: Pure复习笔记5.3.4 Strategy for Trigonometric Equations

Strategy for Trigonometric Equations

How to approach solving trig equations

  • You can solve trig equations in a variety of different ways
    • Sketching a graph (see Graphs of Trigonometric Functions)
    • Using trigonometric identities (see Trigonometry – Simple Identities)
    • Using the CAST diagram (see Linear Trigonometric Equations)
    • Factorising quadratic trig equations (see Quadratic Trigonometric Equations)
  • If you’re having trouble solving a trig equation, this flowchart might help:


Exam Tip

  • Don’t forget to check the function range and ensure you have included all possible solutions.
  • If the question involves a function of x or θ, make sure you transform the range first (and ensure you transform your solutions back again at the end!).

Worked Example