Trigonometric functions The relationship between trigonometric functions and a unit circle A.V.Ali

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

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

sin, cos and tan function

 Radius = 1 1 a b 

  c 1

 cos  sin  tan  Summary

sec, cosec and cot function

 Radius = 1  1  d e

  1 f

 sec  cosec  cot  Summary