5.1 Nonlinear Functions
This is a function which differs from the earlier ones.
y = x^{2}  4
As you see here the one xvariable has the exponent 2. It is called a second degree function.
How does the graph of a second degree function look like?
We begin by choosing a few values of x and making a value table:
We show this with a graph in the coordinate system by plotting in the points and connecting them.
In the coordinate system you can clearly see that the graph doesn’t make a straight line, and it is as such not a linear function. What is special with second degree functions is that:
 they have a maximum value (highest value) or a minimum value (lowest value) for y. In the example above, the function has a minimum value. What determines if it has a max or minimum value is if the mvalue in the second degree function is positive or negative? A positive mvalue gives a minimum value on the yaxis and a negative mvalue gives a max value.
If you want to freshen up your memory about what mvalue is, you can read page 4.2

for each value of y there can be two values of x. This applies for all second degree functions. The exception is the max and minimum values.
