Final answer:
In mathematics, a graph is a visual representation used to show relationships between nodes and edges, commonly used for network and relationship analysis.
Step-by-step explanation:
A graph in the context of mathematics and computer science is a visual representation that consists of nodes (also called vertices) and edges (connections between nodes). It is often used to represent networks, paths, and other relationships in a way that is easier to understand and analyze visually. Graphs are vital in various fields such as computer science for algorithms like searching and networking, in mathematics for studying graph theory, and in economics for illustrating economic models.
Economic models, for example, can be solved algebraically or graphically. Graphs are particularly powerful for illustrating data visually, which helps to show patterns, comparisons, trends, and quantitative relationships. They serve to condense numerical data and provide an intuitive understanding of the data's interconnectedness. Common graph types include the line graph, displaying the relationship between two variables on two axes; the pie graph, representing portions of a whole; and the bar graph, where the height of bars indicates different values to show relationships or comparisons between entities or groups.