5
5
2-D Trigonometry
SUMMARY POINTs
� Consider a triangle ABC : sin A sin B a b
� or � : Sine rule a b sin A sin B Note : The ambiguous case exists if two sides and an angle are known , and the angle is opposite to the shorter known side
� x yrad
� : Method of conversions between degree and radian 180 � rad
� Consider a sector OPRQ with centre O , radius r and �POQ � � in radian : 1 . r� : Arc length PQ
2 .
3 .
1 2
r � : Area of the sector OPRQ 2
1 2
( sin ) 2 r � � � : Area of the segment PRQ
Solutions of Chapter 5
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