AQA A Level Maths: Pure复习笔记5.2.1 Graphs of Trigonometric Functions

Graphs of Trigonometric Functions

Graphs of trigonometric functions

  • The Trigonometric Functions Sin, Cos and Tan all have special periodic graphs that you need to be able to sketch and remember
  • You’ll need to know their properties and how to sketch them to solve equations and for transforming trig functions


Sketching trigonometric graphs


Using trigonometric graphs

  • By sketching the graph you can read off all the solutions in a given range (or interval)
  • Your calculator will only give you the principal value
  • You should recognise any values/angles associated with exact values
  • You should be able to spot the pattern of solutions using the symmetry and periodicity of the graph


Exam Tip

  • Always sketch with a pencil and draw a smooth curve and pay attention to the key features of each graph:
    • Where it crosses the x and y axes
    • How often it repeats
    • Whether it is symmetrical
  • Remember, when answering exam questions that ask for solutions, a sketch will help ensure you give all the appropriate solutions for a given interval.

Worked Example