Apps. and Interpretation for IBDP Maths Ebook 2 | Page 135

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Paper 1 – Adjacency Matrices
Example
Consider the following unweighted graph :
( a )
Write down the degree of D .
( b )
Write down the adjacency matrix M of the graph .
( c )
Hence , find the number of walks of length 2 from A to C .
Solution
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( a ) 3 A1
( b )
( c )
�0 1 0 1� � � 1 0 1 1
M � � �
A2 0 1 0 1
� � �1 1 1 0�
�2 1 2 1�
� �
1 3 1 2 � �
� � 2 1 2 1
� �1 2 1 3� Thus , the number of walks of length 2 from A to
C is 2 .
2
M ( M1 ) for valid approach
A1
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