Chapter 11.1, Problem 24E

To determine

To graph the parabola using graphing device.

Explanation of Solution

Given information: Use graphing device to graph the parabola $x^2=-8y$ .

Graph: to draw the graph using a graphing device, it is needed to solve equation for y.

  $\begin{array}{l}{x}^2=-8y\\ y=-\frac{x^2}{8}\text{ [divide by -8]}\end{array}$

To obtain the graph of the parabola, graph the following functions,

  $y=-\frac{x^2}{8}$

Sketch the graph using graphing utility.

Step 1: Press WINDOW button to access the Window editor.

Step 2: Press $\boxed{\text{Y=}}$ button.

Step 3: Enter the expression $y=-\frac{x^2}{8}$ which is required to graph.

Step 4: Press GRAPH button to graph the function.

The graph is obtained as:

  

Interpretation:

From the above graph, it can be observed that the vertices of the parabola is $\left(0,0\right)$ and focus is $\left(0,-2\right)$ and directrix is $y=2$ .