1 Trigonometric functions for any size angle

  1.1 The radian

2 General definitions of trigonometric functions

  2.1 The sine and cosine of an angle

  2.2 Sine and cosine in the four quadrants

3 Graphs of trigonometric functions

  3.1 Graphs of sin $\theta$ and cos $\theta$

  3.2 The graph of $tan\theta$

4 Engineering Example 4

  4.1 Optical interference fringes due to a glass plate