Analysis and Approaches for IBDP Maths Ebook 2 | Page 12

Your Practice Set – Analysis and Approaches for IBDP Mathematics
1
Paper 1 Section A – Absolute Signs
Example
(a) Solve the inequality 3x�1 � x� 1.
(b) Solve the inequality 3x�1 � x� 1 .
[3]
[4]
Solution
(a) 3x�1 � x�
1
3x�1� x� 1 or 3x�1 � �( x� 1)
M1
3x�1� x� 1 or 3x�1� �x�
1
2x � 0 or 4x �� 2
x � 0 or
(b) 3x�1 � x�
1
1
x �� A2
2
[3]
2 2
3x�1 � x�
1
2 2
9x 6x 1 x 2x
1
� � � � � M1
2
8x
4x
0
� � (A1) for correct inequality
4 x(2x�1) � 0
1
� x � � or x � 0
A2
2
[4]
Exercise 1
1. (a) Solve the inequality 2x�1 � 4x� 1.
(b) Solve the inequality 2x�1 � 4x� 1 .
[3]
[4]
2
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