**Conic sections** or simply conics are the curves obtained by cutting a (double) right circular cone by a plane. Let RS be a line through the center C of a given circle and perpendicular to its plane. Let A be a fixed point on RS. All lines through A and points on the circle generate a right circular cone.

## **Conic Sections**

**Nappes:**Two parts of cone are called nappes.**vertex or apex:**meeting point of two parts of cone are called apex or vertex.**circle:**if cone is cut by the plane perpendicular the axes of the cone then resulting section is called circle. we an also define circle as**“A locus of points which remains at a fixed distance from a certain point.”**the point is called the Centre of circle and fixed distance is called the radius of circle.**Parabola of conic sections:**If the intersecting plane is parallel to the generator of the cone but cut only one nappe is called parabola.**Ellipse of conic sections:**If the cone is cut by the plane and the cutting plan is slightly titled and cut only one nappes of the cone then the resulting section is ellipse.**Hyperbola of conic sections:**If the cone is cut by the plane and the cutting plan is parallels to the axis of the cone and intersects both its nappes , then curve of intersection is hyperbola.**Point circle:**If a plane passes through the vertex of the cone, the intersection is a single point or point circle if r=0**Tangent:**A line that touch the curve without cutting through it is called tangent.**Normal:**A line perpendicular to the tangent is called normal**Chord of contact:**A line joining point of contact of chord.**Eccentriity :**The number e is called eccentricity where e=\frac{\left|PF\right|}{\left|PM\right|}**Centeral conic:**ellipse and hyperbola are called central conics.