Conic Sections: Overview of Circle (
( Click on the Blue Underlined Words for expanded explanations! )
Definition: A circle is a set of points equidistant from a single point. *
Equation: x2 + y2 = r2 Center= (0,0) (x-h)2 + (y-k)2 = r2 Center = (h,k)
Important Concepts for Circles: Center,
Radius, Axis,
Intercept(s)
Eccentricity (e=0) Distance: D=( (x-x)2 + (y-y)2)1/2 Midpoint: M = [(x+x)/2 , (y+y)/2)]
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Determine an equation for a Circle with Center at (0,0) and radius of 3:
|
x2
+ y2 = r2 |
|
|
x2
+ y2 = (3)2 |
|
|
x2 + y2 = 9 |
Determine an equation for a Circle with Center at (3,-2) and
radius of 1:
|
(x-h)2
+ (y-k)2 = R2 |
|
|
(x-3)2
+ (y+2)2 = (1)2
|
|
|
+x2 – 6x +9 +y2 + 4y + 4 = 1 |
|
|
+x2 – 6x +y2 +4y = – 12 |
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Tom Love