This activity consists of 18 statements about trigonometric functions that students must sort into groups of either:
Always True—True for all angles
Sometimes True—True for some angles
Never True—Not True for any angle at all.
One way to do the activity is to ask pupils to cut out the cards and stick them on A3 paper, explaining their reasoning for each card as they stick them into a group. They could explain their reasons using diagrams of the unit circle, or sketches of the trigonometric graphs.
If they believe the statement is sometimes true, they should give examples of when it is and when it isn’t true.
There are two copies of the activity one in radians and one in degrees.
As an extension, students could make up some further examples of cards that will be always, sometimes or never true.
Tags: Trigonometry, Trigonometric Functions, Unit Circle, Sin, Cos, Tan, Trigonometric Graphs,
Common Core Standards:
CCSS.Math.Content.HSF-TF.A.2 Explain how the unit circle in the coordinate plane enables the extension of trigonometric functions to all real numbers, interpreted as radian measures of angles traversed counterclockwise around the unit circle.
CCSS.Math.Content.HSF-TF.A.4 - Use the unit circle to explain symmetry (odd and even) and periodicity of trigonometric functions.