Graphs of Trigonometric Functions (Edexcel IAL Maths)

Spec point — 3.3

Graphs of trigonometric functions

What are the 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

How do I sketch trigonometric graphs?

How do I use 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 Hint

• 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