Quadratic Functions and Models
Basic Forms of a Quadratic Function
There are two basic forms for quadratic functions. The first one (standard form) is f (x) = ax2 + bx + c
and the second one ( vertex form ) is f (x) = a(x - h) 2 + k . The graph of a quadratic function is a
parabola . If a is positive , the parabola opens upward and if a is negative, it opens downward.
Example: Find the vertex .
• In exercises # 103 & 105, you are asked to use least -squares
regression to find a quadratic function that
models the data. This is done almost in exactly the same way that linear regression is done.