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What is the maximum number of edges in an acyclic undirected graph with $n$ vertices?

  1. $n-1$
  2. $n$
  3. $n+1$
  4. $2n-1$
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8 Answers

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An acyclic graph may be a connected graph maybe a disconnected graph. An acyclic-connected graph is a tree and a collection of such trees is known as a forest.

An acyclic undirected graph is given in this question, So it can be a tree or a forest. But we want to maximize the number of edges(maximally connected) without making any cycle. So it must be a tree.

A tree with n vertices will have (n-1) edges.

So the answer is A.

NOTE:

If no of edges is greater than or equal to no of vertices in a graph then the graph must be cyclic.

Ref: Tree (graph theory) - Wikipedia

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The minimum no of edges needed to minimally connect any graph is n-1.Such a graph is called a tree.A tree is 

i)Acyclic and connected → n-1 edges

ii)n-1 edges and connected acyclic

iii)n-1 edges and acyclicconnected 

 

Now addition of 1 more edge will render the graph cyclic 

Correct answer is option B.

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Acyclic graph are graph which doesnt contain cycle

 

here you can see using n vertices , it has maximum n-1 edges.

Answer:

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