8) sin A cos B = ½ [ sin ( A + B ) + sin ( A - B ) ]

   cos A sin B = ½ [sin ( A + B ) - sin ( A - B ) ]

   cos A cos B = ½ [cos ( A + B ) + cos ( A - B ) ]

   sin A sin B = ½ [cos ( A - B ) - cos ( A + B) ]

9) sin P + sin Q = 2 sin cos

sin P - sin Q = 2 cos sin

cos P + cos Q = 2 cos cos

cos P - cos Q = -2 sin sin

   = 2 sin sin

      cos 2A = cos²A - sin²A = 2 cos² A - 1

      = 1 - 2 sin²A =

      tan 2A = ; cot 2 A =

1 + cos q = 2 cos ² q/2 ; 1 - cos q = 2 sin ² q/2

Index

Introduction

1.1 Functions And Mapping
1.2 Functions, Their Graphs and Classification
1.3 Rules for Drawing the Graph of a Curve
1.4 Classification of Functions
1.5 Standard Forms for the equation of a straight line
1.6 Circular Function and Trigonometry

Chapter 2