# Find the Centre, the Lengths of the Axes, Eccentricity, Foci of the Following Ellipse: 4x2 + 16y2 − 24x − 32y − 12 = 0 - Mathematics

Find the centre, the lengths of the axes, eccentricity, foci of the following ellipse:

4x2 + 16y2 − 24x − 32y − 12 = 0

#### Solution

$4 x^2 + 16 y^2 - 24x - 32y - 12 = 0$
$\Rightarrow 4\left( x^2 - 6x \right) + 16\left( y^2 - 2y \right) = 12$
$\Rightarrow 4\left( x^2 - 6x + 9 \right) + 16\left( y^2 - 2y + 1 \right) = 12 + 36 + 16$
$\Rightarrow 4 \left( x - 3 \right)^2 + 16 \left( y - 1 \right)^2 = 64$
$\Rightarrow \frac{\left( x - 3 \right)^2}{16} + \frac{\left( y - 1 \right)^2}{4} = 9$
$\text{ Centre }=\left( 3, 1 \right)$
$\text{ Major axis }=2a$
$= 2 \times 4$
$= 8$
$\text{ Minor axis }=2b$
$= 2 \times 2$
$= 4$
$e = \sqrt{1 - \frac{b^2}{a^2}}$
$\Rightarrow e = \sqrt{1 - \frac{4}{16}}$
$\Rightarrow e = \frac{\sqrt{3}}{2}$
$\text{ Foci } = \left( x \pm ae, y \right)$
$= \left( 3 \pm 2\sqrt{3}, 1 \right)$

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#### APPEARS IN

RD Sharma Class 11 Mathematics Textbook
Chapter 26 Ellipse
Exercise 26.1 | Q 10.5 | Page 23