1. Trigonometric functions The relationship between trigonometric functions and a unit circle A.V.Ali www.2july-maths.co.uk

2. Take a circle with a radius equal to 1 unit Mark a point, A, away from the circle Now draw two tangents from A to the circle A 1

3. Tangents to the circle Radius of the circle A secant line (the line of a chord through a circle)

4. sin, cos and tan function

5.  Radius = 1 1 a b 

6.   c 1

7.  cos  sin  tan  Summary

8. sec, cosec and cot function

9.  Radius = 1  1  d e

10.   1 f

11.  sec  cosec  cot  Summary