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Contents
Conic Sections 1 2
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Conic
Sections
Conic
sections are special graphs. Their shapes can actually be derived from a
cone. They are different from most other graphs that we discuss here as
the y-variable in their equations are usually in second degree.
As
you will soon notice, the general equations for each conic section involve
the variables in x2 and y2 form. Hence, if you see x2
and y2 in an equation, to sketch its graph, simply complete the
square and see which of the following categories it falls under.
Circle
The
general equation of a circle is
(x
- a)2 + (y - b)2 = r2
where
the centre is at (a,b) and radius r.
Graph
of x2 + y2 = 1 Ellipse
The
general equation of an ellipse is
 where
(a,b) is the centre, c is the major axis (the distance from centre
to graph along the horizontal) and d is the minor axis (the
distance from centre to graph along the vertical).
As
you can see, the ellipse is very similar to the circle. Actually, the
circle is a special case of the ellipse, when c = d = 1.
Graph of 
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