Expert: Paul Klarreich - 3/6/2008

Question
I am currently taking part in a computer course, and have to retake a maths exam, as i failed the first time. I found out which questions i was having trouble answering, and so need help.

I am having a lot of trouble with answering questions based on Adjacency Matrix. The following question has three parts. So i want the answers for each part, and if you could provide some details on how i can answer these in the exam. (SEE IMAGES, the excerpt below was taken from a PAST exam paper)

A) http://i28.tinypic.com/2dsipep.jpg
B) http://i32.tinypic.com/2wmnl21.jpg
C) http://i31.tinypic.com/wa4w35.jpg

Thank You

Answer
Questioner:     jason williams
Category:    Advanced Math
Private:    No
Subject:    Adjacency Matrix
Question:    I am currently taking part in a computer course, and have to retake a maths exam, as i failed the first time. I found out which questions i was having trouble answering, and so need help.I am having a lot of trouble with answering questions based on Adjacency Matrix. The following question has three parts. So i want the answers for each part, and if you could provide some details on how i can answer these in the exam. (SEE IMAGES, the excerpt below was taken from a PAST exam paper)

A) http://i28.tinypic.com/2dsipep.jpg
B) http://i32.tinypic.com/2wmnl21.jpg
C) http://i31.tinypic.com/wa4w35.jpgThank You


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Hi, Jason,

In the future, PLEASE don't do that stuff with the images.  If you have a real picture to send, attach it.  But if it's just an image of a question, don't do that.  Type it in.  If you don't understand the question well enough to just copy it, you are not ready for the subject.  

Your matrices are:


A =
0  0  1  0  0
0  0  0  0  1
1  0  0  1  0
0  0  1  0  0
0  1  0  0  0

A =
0  0  1  0  0
0  0  0  0  1
1  0  0  1  0
0  0  1  0  0
0  1  0  0  0

A^2 =
1  0  0  1  0
0  1  0  0  0
0  0  2  0  0
1  0  0  1  0
0  0  0  0  1

Since A^2[


A^2: How many paths between 1 and 3.

I am not sure how to answer B and C.  

Since the graph is symmetric, obviously there is  a path 1 --> 3 and a path 3 --> 1.