The valency of a vertex is the number of lines at that vertex.Each line joins two vertices so each line contributes 2 the the sum of valencies. Since the number of lines must be an integer, the sum of the valencies must be double that number and so it must be even.
-3
3 if n is odd 2 if n is even where n is the number of vertices.
n-1 (o-o-o-o-o)
n * (n - 1) / 2 That would ignore the "acyclic" part of the question. An acyclic graph with the maximum number of edges is a tree. The correct answer is n-1 edges.
No, the complete graph of 5 vertices is non planar. because we cant make any such complete graph which draw without cross over the edges . if there exist any crossing with respect to edges then the graph is non planar.Note:- a graph which contain minimum one edge from one vertex to another is called as complete graph...
The number of vertices in an octagonal pyramid is 9, irrespective of any graph.
11......
The term "cyclic graph" is not well-defined. If you mean a graph that is not acyclic, then the answer is 3. That would be the union of a complete graph on 3 vertices and any number of isolated vertices. If you mean a graph that is (isomorphic to) a cycle, then the answer is n. If you are really asking the maximum number of edges, then that would be the triangle numbers such as n (n-1) /2.
36 vertices if all of them are or order two except one at each end.
A cubic graph must have an even number of vertices. Then, a Hamilton cycle (visiting all vertices) must have an even number of vertices and also an even number of edges. Alternatively color this edges red and blue, and the remaining edges green.
-3
n-1
3 if n is odd 2 if n is even where n is the number of vertices.
V*(V-1)/2
It is a true statement.
In an undirected graph, an edge is an unordered pair of vertices. In a directed graph, an edge is an ordered pair of vertices. The ordering of the vertices implies a direction to the edge, that is that it is traversable in one direction only.
In a connected component of a graph with Mi vertices, the maximum number of edges is MiC2 or Mi(Mi-1)/2. So if we have k components and each component has Mi vertices then the maximum number of edges for the graph is M1C2+M2C2+...+MKC2. Of course the sum of Mi as i goes from 1 to k must be n since the sum of the vertices in each component is the sum of all the vertices in the graph which you gave as n. Where MC2 means choose 2 from M and there are M(M-1)/2 ways to do that.