Trigonometric Graphs (CIE IGCSE Maths: Extended)

Revision Note

Test yourself Flashcards

Author

Daniel I

Last updated

27 July 2023

Did this video help you?

Drawing Trig Graphs

Why do we need to know what trig graphs look like?

Trigonometric graphs (trig graphs) are used in various applications of mathematics
- for example, the oscillating nature can be used to model how a pendulum swings or tide heights

How do we draw trig graphs?

As with other graphs, being familiar with the general style of trigonometric graphs will help you sketch them quickly and you can then use them to find values or angles alongside, or instead of, your calculator
All trigonometric graphs follow a pattern – a “starting point” and then “something happens every 90°”

$y = \sin x$
Starts at (0,0)
Every 90° it cycles through 1, 0, -1, 0, ...

y-equals-sinx

$y = \cos x$
Starts at (0, 1)
Every 90° it cycles through 0, -1, 0, 1, ...

y-equals-cosx

$y = \tan x$
Starts at (0, 0)
Every 90° it is either 0 or an asymptote
- An asymptote is a line that a graph gets ever closer to, without ever crossing or touching it

y-equals-tanx

Worked example

On the axes provided, sketch the graph of $y = \sin x °$ for $0 \leq x \leq 360$ .

Mark key values on the axes provided; 1, 0 and −1 on the y-axis and 0, 90, 180, 270 and 360 on the x-axis. Try to space them evenly apart

IcJiYEqM_2-14-trig-graphs1

For $y = \sin x °$ , the key knowledge is that it starts at (0, 0) then every 90° it cycles though 1, 0 , −1, 0, ... so mark these points on the axes

Finally, join the points with a smooth line. It is best practice to label the curve with its equation

5_-KJTZ8_2-14-trig-graphs2

You've read 0 of your 10 free revision notes

Unlock more, it's free!

Join the 100,000+ Students that ❤️ Save My Exams

the (exam) results speak for themselves:

Test yourself Flashcards

Did this page help you?

Previous:3D Pythagoras & TrigonometryNext:Solving Trig Equations

Author: Daniel I

Expertise: Maths

Daniel has taught maths for over 10 years in a variety of settings, covering GCSE, IGCSE, A-level and IB. The more he taught maths, the more he appreciated its beauty. He loves breaking tricky topics down into a way they can be easily understood by students, and creating resources that help to do this.