Apps. and Interpretation for IBDP Maths Ebook 1 | Page 367

Answers
4.4 (a)
(b)
(c)
(d)
Exercise 5
5
x �
2
7
y �
2
� 7 �
�y:
y � �
� 2�
5
0.760 � x � or x � 7.24
2
5.1 (a) m represents the rate of
change of the boiling point of
water in degrees Celsius per
1 metre increase in vertical
height above the sea level
(b) m ��0.0036
(c) 4440 m
5.2 (a) b represents the initial
number of hotels
(b) a �10
, b �143
(c) 223
5.3 (a) a represents the rate of
change of the daily salary in
dollars per 1 hour increase in
working time
(b) b represents the fixed daily
salary
(c) a � 50 , b � 200
(d) $225
5.4 (a) p represents the rate of
(b)
change of the area of the
2
aluminium lamina in mm
per 1 degree Celsius increase
in temperature
q represents the area of the
aluminium lamina at 0C
(c) p � 0.05 , q � 5
(d)
2
7 mm
Chapter 4
Exercise 6
6.1 (a) 2 and 4
(b) (i) x � 3
(ii) � 1
6.2 (a) 1 and 10
(b) (i) x � 5.5
(ii) � 20.25
6.3 (a) 0 and � 7
(b) (i) x �� 3.5
(ii) 24.5
6.4 (a) � 3 and 3
(b) (i) x � 0
(ii) 13.5
Exercise 7
7.1 (a) f ( x) � ( x �7)( x � 5)
(b) x �� 5 and x � 7
(c) { y: y�� 36}
7.2 (a) f ( x) � �2( x �1)( x � 6)
(b) x �� 1 and x �� 6
(c) { y: y� 12.5}
7.3 (a) p � 5 and q � 11
(b) a � 1.5
(c) { y: y�� 13.5}
7.4 (a) p � 0 and q � 18
(b)
2
a �
3
(c) { y: y� 54}
Exercise 8
8.1 (a) x � 2
(b) (2,17)
(c) { y: y� 17}
8.2 (a) 4
(b) (7, � 2)
(c) { y: y�� 2}
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