5.4A  Finding Vertex and Axis of Symmetry

Quadratic Functions

A quadratic function is defined as follows: 

f(x) = ax2+ bx + c where a, b, and c are real numbers and "a" cannot equal 0, its domain is the set of all real numbers.

 Another form of a quadratic function is f(x) = a(x - h)2+ k, where  "a" cannot equal zero (h, k) are the coordinates of the vertex of the function and its graph.

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Methods used to find vertex and axis of symmetry

     If the quadratic function is in the following form:

                    ax2 + bx + c = y

     ~   Use a, b, and c to find the x value of the vertex.

     ~   Plug x into the function to find the y value.

     ~   (x, y) will be the vertex of the function.

     ~   x = value is the axis of symmetry.

    The formula we are going to use is derived from the quadratic formula.