When the radical of a radical function is a square root, it is called a square root function. The parent function of the square root function family is
When the radical is a cube root instead, it is called a cube root function. The parent function of the family of cube root functions is
With the help of tables, graph the given functions. Then, for both functions, give their following features:
Let's start by graphing This is a square root function, so it is not defined when the expression inside the radical is negative. Thus, it is best to start our table with which leads to under the radical.
We can now plot the corresponding points in a coordinate plane. Connecting the points with a smooth curve gives us the desired graph. Note that the function is not defined for less than
Notice that is a cube root function — it is defined for all values of Thus, we'll use both positive and negative values for the table.
Let's plot the points and connect them with a smooth curve. Since the domain of this function is all real numbers, the graph should continue infinitely in both directions.
To determine the stated key features, we'll analyze each graph. Both these functions extend upward as extends to positive infinity. However, their left-ends differ, as is not defined for less than while extends downward. For a function to have even or odd symmetry, it has to fulfill respectively. Graphically, this is a symmetry in the -axis or about the origin, respectively. has neither of these, while has odd symmetry — opposite sign of the input yields opposite sign of the output. Assuming no other behavior of the functions than that seen in the graphs, both functions are increasing for their entire domain.