A polynomial equation in which the highest power of the variable is 2 is called a quadratic function. We arrive at the following graph when we draw up a quadratic function such as **y = x**^{2}
We can easily see that we are not dealing with a straight line but a parabola, thus it is referred to as a non-linear function. When one has a positive coefficient before **x**^{2} we have a minimum value, and if we have a negative coefficient we have a maximum value instead. See the graph below where **y = -x**^{2}:
We graph our quadratic function in the same way as we graph a linear function. First we make a table for our x- and y-values. From the x values we determine our y-values.
Last we graph our matching x- and y-values and draw our parabola. |