Quadratic function is a function that can be described by an equation of the form f(x) = ax^{2} + bx + c, where a ≠ 0.

In a quadratic function, the greatest power of the variable is 2. The graph of a quadratic function is a parabola.

More About Quadratic Function

Quadratic equation: An equation in the standard form ax^{2} + bx + c = 0, where a ≠ 0 is called a quadratic equation. Quadratic formula: A quadratic formula is the solution of a quadratic equation ax^{2} + bx + c = 0, where a ≠ 0, given by Quadratic inequality: An inequality written in one of the forms y <ax^{2} + bx + c, y ≥ ax^{2} + bx + c, y ≤ ax^{2} + bx + c, or y > ax^{2} + bx + c is called a quadratic inequality. Quadratic term: A term ax^{2} is the quadratic term in the equation f(x) = ax^{2} + bx + c

Examples of Quadratic Function

The following are few examples of quadratic functions.

Video Examples: Quadratic Functions

Solved Example on Quadratic Function

Ques: Graph the quadratic function y = - (1/4)x^{2}.Indicate whether the parabola opens up or down.

Choices:

A. Graph-A; opens down
B. Graph-B; opens down

Correct Answer: A

Solution:

Step 1: Make a table of ordered pairs for the given function.

Step 2: Plot these points on the coordinate plane and connect the points with a smooth curve.
Step 3: The graph looks like the one below

Step 4: It can be observed from the graph that the parabola opens down.
Step 5: The equation of the axis of symmetry is: x = 0
Step 6: The vertex is at (0, 0)
Step 7: The parabola opens down. So, the vertex is the maximum point.