The area of the rectangle formed by the perpendiculars from the centre of the standard ellipse to the tangent and normal at its point whose eccentric angle is $\pi /4$ is :
$\frac{{\left( {{a^2}\,\, - \,\,{b^2}} \right)\,\,ab}}{{{a^2}\,\, + \,\,{b^2}}}$
$\frac{{\left( {{a^2} - {b^2}} \right)}}{{\left( {{a^2} + {b^2}} \right)ab}}$
$\frac{{\left( {{a^2}\,\, - \,\,{b^2}} \right)}}{{ab\,\,\left( {{a^2}\,\, + \,\,{b^2}} \right)}}$
$\frac{{{a^2}\,\, + \,\,{b^2}}}{{\left( {{a^2}\,\, - \,\,{b^2}} \right)\,\,ab}}$
The distance of the point $'\theta '$on the ellipse $\frac{{{x^2}}}{{{a^2}}} + \frac{{{y^2}}}{{{b^2}}} = 1$ from a focus is
If the length of the latus rectum of an ellipse is $4\,units$ and the distance between a focus and its nearest vertex on the major axis is $\frac {3}{2}\,units$ , then its eccentricity is?
The equation of the ellipse whose vertices are $( \pm 5,\;0)$ and foci are $( \pm 4,\;0)$ is
The eccentricity of the ellipse $\frac{{{{(x - 1)}^2}}}{9} + \frac{{{{(y + 1)}^2}}}{{25}} = 1$ is
The equation of normal at the point $(0, 3)$ of the ellipse $9{x^2} + 5{y^2} = 45$ is