Trigonometry



__TRIGONOMETRY__

This topic area is dedicated to the study of Trigonometry, the study of the relations of sides and angles of triangles. This topic area is crucial to engineering, design and construction.

The topic will cover:

l How are sin, cos and tan defined using a right-angled triangle? l How can the trigonometric ratios be used to find the side lengths or angles in right-angled triangles and in real world examples? l What is meant by an angle of elevation or an angle of depression and use this to solve real problems? l How are compass bearings and true bearings measured to solve navigation problems? l How can the sine and cosine rules be used to solve non-right-angled triangles? l What are the three rules that can be used to find the area of a triangle?

trigonometry comes from the Greek words "trigonon" which means triangle, and "metria" which means measure.

The three trigonometric ratios are Cosine, Sine and Tangent. They are explained in the power point below:

Video: []

Using the Trig Ratio we are able to find the lengths of the hypotenuse and the two shorter sides and an angle given two sides using the techniques shown below:

It is important when dealing with worded questions that we keep in mind the 6 steps:


 * 1) Draw the diagram
 * 2) Lable the sides and angles
 * 3) Identify the Ratio
 * 4) Replace the terms with known values
 * 5) Rearrange the equation to make the unknown value the subject
 * 6) use your calculator to find the unknown value

These techniques can be used when dealing with angles of elevation (angles upwards from the horizontal) and angles of deperession (angles downwards from the horizontal)

Trigonometry is also used in navigation where TRUE and CONVENTIONAL bearings are used to describe the movement of people, ships etc.

__Revision Questions__

__Important dates__

Wed 11th August - SAQ and EAQ submissions Thurs 12th August - SAC