Tangent and Normal to an Ellipse
Tangent and Normal to an Ellipse: Overview
This topic covers concepts such as Shortest Distance between Line and Ellipse, Tangent to Ellipse, Point Form of Tangent to Standard Ellipse, Parametric Form of Tangent to Standard Ellipse, and Point of Intersection of Tangents in Parametric Form.
Important Questions on Tangent and Normal to an Ellipse
The equation of the normal at the point to the ellipse is

Equations of the common tangent of the ellipse and the circle are

The product of the perpendiculars drawn from the foci of the ellipse upon the tangent to it at the point , is

Equation of the ellipse with axes coinciding the co-ordinate axes touches the straight lines and , is:

The number of values of '' such that the straight line touches the curve , is

If the normal at an end of a latus rectum of an ellipse passes through one extremity of the minor axis, then the eccentricity of the ellipse is given by

The equation of the tangents to the ellipse from the point are -

Equation of the ellipse with axes coinciding the co-ordinate axes touches the straight lines and , is:

Equation of tangents to the ellipse , which are perpendicular to the line , are

The area (in sq. units) of the quadrilateral formed by the tangents at the end points of the latus ractum to the ellipse is

Consider the curve . The portion of the tangent at any point of the curve intercepted between the point of contact and the directrix subtends at the corresponding focus an angle of

The length of the minor axis (along -axis) of an ellipse in the standard form is . If this ellipse touches the line, ; then its eccentricity is:

Let the line and the ellipse intersect at a point in the first quadrant. If the normal to this ellipse at meets the co-ordinate axes at and , then is equal to

The equation of the tangent to the ellipse , and perpendicular to the line is

Consider a tangent to the ellipse at any point. The locus of the mid-point of the portion intercepted between the axes is

The product of the perpendicular distances drawn from the points and to the tangent of an ellipse at is

For the ellipse if a tangent with slope intersects the major and minor axes at and respectively, find and

Find the condition for the line to be a normal to an ellipse

Slope of normal to the ellipse at a point is and eccentricity of ellipse is . If this normal makes acute angle with its focal chord through , then is

Let the ellipse, pass through the point and have eccentricity equal to Then equation of the normal to this ellipse at is
