Unformatted text preview: that opens up
will always open up. In other words a parabola will not all of a sudden turn around and start
opening up if it has already started opening down. Similarly, if it has already started opening up
it will not turn around and start opening down all of a sudden.
The dashed line with each of these parabolas is called the axis of symmetry. Every parabola has
an axis of symmetry and, as the graph shows, the graph to either side of the axis of symmetry is a
mirror image of the other side. This means that if we know a point on one side of the parabola we
will also know a point on the other side based on the axis of symmetry. We will see how to find
this point once we get into some examples.
We should probably do a quick review of intercepts before going much farther. Intercepts are the
points where the graph will cross the x or y-axis. We also saw a graph in the section where we
introduced intercepts where an intercept just touched the axis without actually crossing it.
Finding intercepts is a fairly sim...
View Full Document
This note was uploaded on 06/06/2012 for the course ICT 4 taught by Professor Mrvinh during the Spring '12 term at Hanoi University of Technology.
- Spring '12