Trigonometry

Trigonometry is a really important topic. In the past, it has appeared in both sections of the paper. You need to master the skills involved in all aspects of this topic.

Students need to be able to solve triangles. Be familiar with the formulae in the log tables. Practise how to find sides, angles and area. Make sure to know which formulae are used for right angled triangles and which ones are used for other triangles. Students can be asked to solve 2D or 3D problems. Example: In a triangle XYZ,

|∠

|XY|=3cm,|YZ|=5cm and XYZ|=60°. Find

|XZ|. You need to be able to define sinθ,cosθ and tanθ for all values of θ. Also solve trigonometric equations such as sin nθ =0 and cos nθ = giving all solutions Find where cos x is negative:

2nd and 3rd quadrants. Therefore,

2x = (180 – 60)° = 120° and

(120 + 360) = 480°.

Also 2x = (180+60)° = 240°, and (240 + 360) = 600° Dividing by 2, we find that x = 60°,120°,240°,300°

Solve problems involving the area of a sector of a circle and the length of an arc. Be able to use the relevant formulae.

Graph the trigonometric functions and be able to solve problems involving the graphs. Example: Write down the period and range of the function f(x )=5+3cos2 x and graph the function. Period =[2,8]