Introduction to trigonometry
What is trigonometry? The branch of mathematics called trigonometry deals with the relationship between the side lengths and angles in triangles.
Trigonometry dates back to the ancient Egyptian and Babylonian civilizations where a basic form of trigonometry was used in building the pyramids and also in the study of astronomy!
Some important features we will have to know The hypotenuse is the longest side and is always opposite the 90° angle The opposite side is opposite the angle (theta) The adjacent side is next to the angle (theta)
The trigonometric ratios
Here is a useful way of remembering the three ratios
Examples
Cambridge exercises Chapter 3E Trigonometric Ratios Questions 1, 2a –d , 3, 4a, c, e, h 5 a, b 6 a – c 8 & 9
Homework CAMBRIDGE EXERCISE 3E 2e – h 4b, d, f, g 5c 7a – c