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# 5: Quadratic Functions

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• 5.1: The Parabola
In this section you will learn how to draw the graph of the quadratic function defined by the equation f(x)=a(x−h)2+k. You will quickly learn that the graph of the quadratic function is shaped like a "U" and is called a parabola. The form of this quadratic function is called vertex form, so named because the form easily reveals the vertex or “turning point” of the parabola. Each of the constants in the vertex form of the quadratic function plays a role.
• 5.2: Vertex Form
Once you have your quadratic function in vertex form, the technique of the previous section should allow you to construct the graph of the quadratic function. However, before we turn our attention to the task of converting the general quadratic into vertex form, we need to review the necessary algebraic fundamentals.
• 5.3: Zeros of the Quadratic
When drawing the graph of the parabola it is helpful to know where the graph of the parabola crosses the x-axis. That is the primary goal of this section, to find the zero crossings or x-intercepts of the parabola.
• 5.4: The Quadratic Formula
The equation ax²+bx+c=0 is called a quadratic equation. Previously, we solved equations of this type by factoring and using the zero product property. It is not always possible to factor the trinomial on the left-hand side of the quadratic equation as a product of factors with integer coefficients and we’ll need another method to solve the quadratic equation; the purpose of this section is to develop a formula that will consistently provide solutions of the general quadratic equation.
• 5.5: Motion
If a particle moves with uniform or constant acceleration, then it must behave according to certain standard laws of kinematics. In this section we will develop these laws of motion and apply them to a number of interesting applications.
• 5.6: Optimization
Optimization can be applied to a broad family of different functions. However, in this section, we will concentrate on finding the maximums and minimums of quadratic functions. There is a large body of real-life applications that can be modeled by quadratic functions, so we will find that this is an excellent entry point into the study of optimization.