Write the equation of each conic described below.
A circle whose center lies on the line
. The circle has a radius of and is tangent to the -axis.
-coordinate of the circle must be either or . Why?
A parabola with the focus at
and a directrix of .
This parabola opens to the left. Why?
Sketch the situation to help locate the vertex and determine the value of
Review the Math Notes box in Lesson 11.1.5.