5
Parabolas
1
Introduction
When looking at a cone, a parabola will be created if the plane is cuts the top and the diagonal of one cone. A parabola is the
set of all points euidistant from a fixed line, called the directrix, and a fixed point not on the line, called the focus. The vertex form for a parabola is:
3
Practice Identifying
Now you will use a desmos manipulative to identify how h and k effect the equation the graph of the parabola.
Click the parabola graphs below. It will take you
to the desmos site. Slide the blue bottom under the a.
How does the a value effect the graph of the parabola? Can the parabola open in any direction?
2
Practice Graphing
Using desmos.com, type the following parabola equations into the graphing calucaltor.
What compare and contrast graph 1 and 2. Did the h and k values act the same way as the circles and ellipses?
4
Your Turn
Now try graphing the following equations on graph paper. Label the vertex, the axis of symmetry, and find two additional
points. You can check your answers usiing the desmos online graphing calculator or in the back of this book.