In this worksheet, you will determine whether the trigonometric function of any angle is positive or negative.
All angles (other than multiples of 90º) fall into one of four quadrants.
Look at the following diagram:
Angles are measured anticlockwise from the 0º line.
In the diagram above, you should notice that 200º lies in the 3rd quadrant.
The following diagram shows the trigonometric functions which are POSITIVE in the quadrant shown.
Remember ASTC (ALL SIN TAN COS or "All Silly Tom Cats")
State which of sin 200º, cos 200º or tan 200º is positive.
Draw 200º on the ASTC circle.
It shows that the only trig ratio that is positive is tan 200º.
State which of sin 300º, cos 300º or tan 300º is positive.
Draw 300º on the ASTC circle.
It shows that the only trig ratio that is positive is cos 300º.