Apps. and Interpretation HL Practice Paper Book | Page 23

www . seprodstore . com 11 � Trigonometric identities : 1 . sin tan cos � � � � 2 . 2 2 sin cos 1 � � � � � ASTC diagram � Consider a triangle ABC : 1 . sin sin A B a b � or _{sin sin} a b A B � : Sine rule 2 . 2 2 2 2 cos a b c bc A � � � or 2 2 2 cos 2 b c a A bc � � � : Cosine rule 3 . 1 sin 2 ab C : Area of the triangle ABC � Consider a sector OPRQ with centre O , radius r and POQ � � � : 2 360 r � � � : Arc length PRQ 2 360 r � � � : Area of the sector OPRQ 2 2 1 sin 360 2 r r � � � � � : Area of the segment PRQ y x 13 2-D Trigonometry