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1- Which of the following graphs are connected? --------------------------------

ID: 2903196 • Letter: 1

Question

1-

Which of the following graphs are connected?

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Which of the following graphs have Euler circuits?

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3-Which of the following graphs have hamiltonian circuits?

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4-

What is the edge set?

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5-

Theorem (MAT114 Website Section 5B)

How many Hamiltonian circuits are there in a complete graph with 8 vertices?

How many Hamiltonian circuits are there in a complete graph with 5 vertices?

A B C

D

Explanation / Answer

1. In a connected graph, there exists a path between any two vertices on the graph. A, C, and D are connected. B is not.

2. A graph contains an Euler circuit if a) it is connected, and b) it has 0 odd vertices. A and B contain Euler circuits.

3. To know if it has a Hamiltonian circuit, you pretty much just have to try to find one. A Hamiltonian circuit is a circuit that visits each vertex exactly once before returning to the starting vertex. A and D definitely have Hamiltonian circuits and C does not. I couldn't find any for B, but I'm not sure there definitely isn't one.

4. Draw a connected graph with all even vertices where P has a degree of 4. To get the edge set, list all the edges. For the graph that I drew, the edge set is {PM, MO, ON, NP, PO, OR, RQ, QP}.

5. Plug into the given formula. a) 7!/2 = 2,520 b) 4!/2 = 12

Hope this helps!