Understanding the Graph of a Quadratic Function

A quadratic function is a type of function that describes the relationship between a variable and its square. It is an equation of the form y=ax2 + bx + c, where a, b, and c are constants and x is the independent variable. The graph of a quadratic function is a parabola, and it can be used to identify the properties of the function. This article will provide an overview of the graph of a quadratic function, including how to identify the key features of the graph, how to identify the turning points and the vertex, and how to use the graph to solve problems.

Identifying Key Features of the Graph

Identifying Key Features of the Graph

The graph of a quadratic function is a parabola, and it is symmetrical about the y-axis. The graph increases or decreases from the y-axis depending on the sign of the coefficient of x2. If the coefficient of x2 is positive, the graph increases from the y-axis; if it is negative, the graph decreases from the y-axis. The shape of the graph is determined by the coefficient of x2; if the coefficient is greater than one, the graph is wider; if the coefficient is less than one, the graph is narrower. The graph also passes through the origin, which is the point (0, 0).

Identifying the Turning Points and Vertex

Identifying the Turning Points and Vertex

The turning points of the graph are the points at which the graph changes direction; they are also called the stationary points. The turning points can be found by taking the derivative of the function and solving for x. The x-coordinate of the turning points is the same as the x-coordinate of the vertex. The vertex of the graph is the point at which the graph reaches its highest or lowest point. The coordinates of the vertex can be found by solving the quadratic equation for x.

Using the Graph to Solve Problems

Using the Graph to Solve Problems

The graph of a quadratic function can be used to solve problems related to the function. For example, the graph can be used to find the maximum or minimum values of the function. The maximum or minimum values are given by the x-coordinate of the vertex. The graph can also be used to solve equations involving the function. For example, the x-coordinates of the intersection points of the graph with the x-axis can be used to find the solutions of the equation. Finally, the graph can be used to estimate the values of the function at certain points.



The graph of a quadratic function is a parabola, and it can be used to identify the properties of the function. The turning points and vertex of the graph can be found by taking the derivative of the function and solving for x. The graph can also be used to solve equations involving the function and to estimate the values of the function at certain points. Understanding how to interpret the graph of a quadratic function is essential for solving problems involving quadratic functions.