4. This chapter is about
parabola, hyperbolas, circles, ellipses.
the names parabola and hyperbola are
given by Apollonius.
These curves are in fact, known as
conic sections or more commonly
conics because they can be obtained
as intersections of a plane with
double napped right circular cones.
5.
6.
7.
8. When the plane cuts at the vertex of
the cone, we have the following
different cases:
When α < β ≤ 90 then the section is a
point.
When β = α the plane contains a
generator of the cone and the section
is a straight line.
When 0≤ β < α the section is a pair of
intersecting straight lines.
15. Latus rectum of a parabola is a line segment
perpendicular to the axis of the parabola, through
the focus and whose end points lie on the
parabola
Length of latus rectum= 4a.
16. An ellipse is the set of all the points in a plane,
the sum of whose distances from two fixed
points in the plane is a constant.
17. Major axis= 2a.
Minor axis=2f
Foci=2c.
Relationship:
A²=b²+c².
C=√a²-b².
18. The eccentricity of an ellipse
is the ratio of the distances
from the centre of the
ellipse to one of the foci
and to one of the vertices of
the ellipse.It is denoted by
e= c⁄a.
19.
20. Latus rectum of an ellipse is a line
segment perpendicular to the
major axis through any of the foci
and whose end points lie on the
ellipse.
Length of the latus rectum of an
ellipse:
23. Latus rectum of an hyperbola
is a line segment perpendicular
to the transverse axis through
any of the foci and whose end
points lie on the hyperbola.
Length of latus rectum in
hyperbola:
2b2/a