Consider a hyperbola $\mathrm{H}$ having centre at the origin and foci on the $\mathrm{x}$-axis. Let $\mathrm{C}_1$ be the circle touching the hyperbola $\mathrm{H}$ and having the centre at the origin. Let $\mathrm{C}_2$ be the circle touching the hyperbola $\mathrm{H}$ at its vertex and having the centre at one of its foci. If areas (in sq units) of $C_1$ and $C_2$ are $36 \pi$ and $4 \pi$, respectively, then the length (in units) of latus rectum of $\mathrm{H}$ is
$x^2-y^2 \operatorname{cosec}^2 \theta=5$ is $\sqrt{7}$ times eccentricity of the
ellipse $x^2 \operatorname{cosec}^2 \theta+y^2=5$, then the value of $\theta$ is :
If the foci of a hyperbola are same as that of the ellipse $\frac{x^2}{9}+\frac{y^2}{25}=1$ and the eccentricity of the hyperbola is $\frac{15}{8}$ times the eccentricity of the ellipse, then the smaller focal distance of the point $\left(\sqrt{2}, \frac{14}{3} \sqrt{\frac{2}{5}}\right)$ on the hyperbola, is equal to
Let $P$ be a point on the hyperbola $H: \frac{x^2}{9}-\frac{y^2}{4}=1$, in the first quadrant such that the area of triangle formed by $P$ and the two foci of $H$ is $2 \sqrt{13}$. Then, the square of the distance of $P$ from the origin is
Let $e_1$ be the eccentricity of the hyperbola $\frac{x^2}{16}-\frac{y^2}{9}=1$ and $e_2$ be the eccentricity of the ellipse $\frac{x^2}{a^2}+\frac{y^2}{b^2}=1, \mathrm{a} > \mathrm{b}$, which passes through the foci of the hyperbola. If $\mathrm{e}_1 \mathrm{e}_2=1$, then the length of the chord of the ellipse parallel to the $x$-axis and passing through $(0,2)$ is :
Let $\mathrm{S}$ be the focus of the hyperbola $\frac{x^2}{3}-\frac{y^2}{5}=1$, on the positive $x$-axis. Let $\mathrm{C}$ be the circle with its centre at $\mathrm{A}(\sqrt{6}, \sqrt{5})$ and passing through the point $\mathrm{S}$. If $\mathrm{O}$ is the origin and $\mathrm{SAB}$ is a diameter of $\mathrm{C}$, then the square of the area of the triangle OSB is equal to __________.
Explanation:
$\begin{aligned} & \frac{x^2}{3}-\frac{y^2}{5}=1 \\ & 5=3\left(e^2-1\right) \Rightarrow e=\sqrt{\frac{8}{3}} \\ & S \equiv(2 \sqrt{2}, 0) \end{aligned}$

$A$ is mid-point of $B S$
$\Rightarrow \quad B(2 \sqrt{6}-2 \sqrt{2}, 2 \sqrt{5})$
$\Delta (OSB) = \left| {{1 \over 2}\left| {\matrix{ 0 & 0 & 1 \cr {2\sqrt 2 } & 0 & 1 \cr {2\sqrt 6 - 2\sqrt 2 } & {2\sqrt 5 } & 1 \cr } } \right|} \right| = 2\sqrt {10} $<./p>
$(\Delta(O S B))^2=40$
The length of the latus rectum and directrices of hyperbola with eccentricity e are 9 and $x= \pm \frac{4}{\sqrt{3}}$, respectively. Let the line $y-\sqrt{3} x+\sqrt{3}=0$ touch this hyperbola at $\left(x_0, y_0\right)$. If $\mathrm{m}$ is the product of the focal distances of the point $\left(x_0, y_0\right)$, then $4 \mathrm{e}^2+\mathrm{m}$ is equal to _________.
Explanation:

$y=m x \pm \sqrt{a^2 m^2-b^2}$ is the tangent
$\begin{aligned} & \Rightarrow m=\sqrt{3} \Rightarrow a^2 m^2-b^2=3 \\ & \Rightarrow 3 a^2-b^2=3 \end{aligned}$
$\begin{aligned} & \frac{2 b^2}{a}=9 \Rightarrow b^2=\frac{9 a}{2} \Rightarrow 3 a^2-\frac{9 a}{2}=3 \\ & \Rightarrow a^2-\frac{3}{2} a-1=0 \\ & \Rightarrow a=2 \text { or }-0.5 \text { (ignore) } \\ & \Rightarrow b=3 \\ & \Rightarrow \frac{x^2}{4}-\frac{y^2}{9}=1 \\ & \Rightarrow \text { Solving hyperbola and tangent } y=\sqrt{3 x}-\sqrt{3} \\ & x_0=4, y_0=3 \sqrt{3}, e=\sqrt{1+\frac{9}{4}}=\frac{\sqrt{13}}{2} \\ & P F_1 \cdot P F_2= \\ & \sqrt{(4-\sqrt{13})^2+(3 \sqrt{3})^2} \sqrt{(4+\sqrt{13})^2+(3 \sqrt{3})^2} \\ & =\sqrt{(56-8 \sqrt{13})(56+8 \sqrt{13})} \\ & =\sqrt{2304}=48=m \\ & \Rightarrow 4 e^2+m=13+48=61 \end{aligned}$
Let the foci and length of the latus rectum of an ellipse $\frac{x^2}{a^2}+\frac{y^2}{b^2}=1, a>b b e( \pm 5,0)$ and $\sqrt{50}$, respectively. Then, the square of the eccentricity of the hyperbola $\frac{x^2}{b^2}-\frac{y^2}{a^2 b^2}=1$ equals
Explanation:
$\begin{aligned} & \text { focii } \equiv( \pm 5,0) ; \frac{2 b^2}{a}=\sqrt{50} \\ & a=5 \quad b^2=\frac{5 \sqrt{2} a}{2} \\ & b^2=a^2\left(1-e^2\right)=\frac{5 \sqrt{2} a}{2} \end{aligned}$
$\begin{aligned} & \Rightarrow \mathrm{a}\left(1-\mathrm{e}^2\right)=\frac{5 \sqrt{2}}{2} \\ & \Rightarrow \frac{5}{\mathrm{e}}\left(1-\mathrm{e}^2\right)=\frac{5 \sqrt{2}}{2} \\ & \Rightarrow \sqrt{2}-\sqrt{2} \mathrm{e}^2=\mathrm{e} \\ & \Rightarrow \sqrt{2} \mathrm{e}^2+\mathrm{e}-\sqrt{2}=0 \\ & \Rightarrow \sqrt{2} \mathrm{e}^2+2 \mathrm{e}-\mathrm{e}-\sqrt{2}=0 \\ & \Rightarrow \sqrt{2} \mathrm{e}(\mathrm{e}+\sqrt{2})-1(1+\sqrt{2})=0 \\ & \Rightarrow(\mathrm{e}+\sqrt{2})(\sqrt{2} \mathrm{e}-1)=0 \\ & \therefore \mathrm{e} \neq-\sqrt{2} ; \mathrm{e}=\frac{1}{\sqrt{2}} \end{aligned}$
$\begin{aligned} & \frac{\mathrm{x}^2}{\mathrm{~b}^2}-\frac{\mathrm{y}^2}{\mathrm{a}^2 \mathrm{~b}^2}=1 \quad \mathrm{a}=5 \sqrt{2} \\ & b=5 \\ & a^2 b^2=b^2\left(e_1^2-1\right) \Rightarrow e_1^2=51 \\ & \end{aligned}$
Let the latus rectum of the hyperbola $\frac{x^2}{9}-\frac{y^2}{b^2}=1$ subtend an angle of $\frac{\pi}{3}$ at the centre of the hyperbola. If $\mathrm{b}^2$ is equal to $\frac{l}{\mathrm{~m}}(1+\sqrt{\mathrm{n}})$, where $l$ and $\mathrm{m}$ are co-prime numbers, then $\mathrm{l}^2+\mathrm{m}^2+\mathrm{n}^2$ is equal to ________.
Explanation:
LR subtends $60^{\circ}$ at centre

$\begin{aligned} & \Rightarrow \tan 30^{\circ}=\frac{\mathrm{b}^2 / \mathrm{a}}{\mathrm{ae}}=\frac{\mathrm{b}^2}{\mathrm{a}^2 \mathrm{e}}=\frac{1}{\sqrt{3}} \\ & \Rightarrow \mathrm{e}=\frac{\sqrt{3} \mathrm{~b}^2}{9} \end{aligned}$
Also, $\mathrm{e}^2=1+\frac{\mathrm{b}^2}{9} \Rightarrow 1+\frac{\mathrm{b}^2}{9}=\frac{3 \mathrm{~b}^4}{81}$
$\begin{aligned} & \Rightarrow \mathrm{b}^4=3 \mathrm{~b}^2+27 \\ & \Rightarrow \mathrm{b}^4-3 \mathrm{~b}^2-27=0 \\ & \Rightarrow \mathrm{b}^2=\frac{3}{2}(1+\sqrt{13}) \\ & \Rightarrow \ell=3, \mathrm{~m}=2, \mathrm{n}=13 \\ & \Rightarrow \ell^2+\mathrm{m}^2+\mathrm{n}^2=182 \end{aligned}$
The transformed equation of $x^2-y^2+2 x+4 y=0$ when the origin is shifted to the point $(-1,2)$ is
If $e_1$ and $e_2$ are respectively the eccentricities of the hyperbola $\frac{x^2}{a^2}-\frac{y^2}{b^2}=1$ and its conjugate hyperbola, then the line $\frac{x}{2 e_1}+\frac{y}{2 e_2}=1$ touches the circle having centre at the origin, then its radius is
Let R be a rectangle given by the lines $x=0, x=2, y=0$ and $y=5$. Let A$(\alpha,0)$ and B$(0,\beta),\alpha\in[0,2]$ and $\beta\in[0,5]$, be such that the line segment AB divides the area of the rectangle R in the ratio 4 : 1. Then, the mid-point of AB lies on a :
Let $\mathrm{P}\left(x_{0}, y_{0}\right)$ be the point on the hyperbola $3 x^{2}-4 y^{2}=36$, which is nearest to the line $3 x+2 y=1$. Then $\sqrt{2}\left(y_{0}-x_{0}\right)$ is equal to :
Let T and C respectively be the transverse and conjugate axes of the hyperbola $16{x^2} - {y^2} + 64x + 4y + 44 = 0$. Then the area of the region above the parabola ${x^2} = y + 4$, below the transverse axis T and on the right of the conjugate axis C is :
The foci of a hyperbola are $( \pm 2,0)$ and its eccentricity is $\frac{3}{2}$. A tangent, perpendicular to the line $2 x+3 y=6$, is drawn at a point in the first quadrant on the hyperbola. If the intercepts made by the tangent on the $\mathrm{x}$ - and $\mathrm{y}$-axes are $\mathrm{a}$ and $\mathrm{b}$ respectively, then $|6 a|+|5 b|$ is equal to __________
Explanation:
Given that the foci are at $(\pm 2, 0)$, the distance between the foci is $2ae = 2\times2 = 4$.
So, $a = \frac{4}{3}$.
The eccentricity of the hyperbola is given as $\frac{3}{2}$. Thus, $e = \frac{3}{2}$.
For a hyperbola, $e^2 = 1 + \frac{b^2}{a^2}$, which gives $b^2 = a^2(e^2 - 1)$.
Substituting the given values, we get $b^2 = \frac{16}{9} - \frac{16}{9} = \frac{20}{9}$.
The equation of the hyperbola is $\frac{x^2}{a^2} - \frac{y^2}{b^2} = 1$, or $\frac{9x^2}{16} - \frac{9y^2}{20} = 1$.
The slope of the tangent line, which is perpendicular to the given line $2x + 3y = 6$, is $\frac{3}{2}$.
The equation of the tangent to a hyperbola is $y = mx \pm \sqrt{a^2 m^2 - b^2}$. Substituting the given values, we get $y = \frac{3x}{2} \pm \sqrt{\frac{16}{9}\times\frac{9}{4} - \frac{20}{9}} = \frac{3x}{2} \pm \frac{4}{3}$.
The $x$-intercept occurs when $y = 0$, so $|a| = \frac{8}{9}$, and the $y$-intercept occurs when $x = 0$, so $|b| = \frac{4}{3}$.
Finally, $|6a| + |5b| = 6\frac{8}{9} + 5\frac{4}{3} = \frac{48}{9} + \frac{60}{9} = \frac{108}{9} = 12$.
Let $m_{1}$ and $m_{2}$ be the slopes of the tangents drawn from the point $\mathrm{P}(4,1)$ to the hyperbola $H: \frac{y^{2}}{25}-\frac{x^{2}}{16}=1$. If $\mathrm{Q}$ is the point from which the tangents drawn to $\mathrm{H}$ have slopes $\left|m_{1}\right|$ and $\left|m_{2}\right|$ and they make positive intercepts $\alpha$ and $\beta$ on the $x$-axis, then $\frac{(P Q)^{2}}{\alpha \beta}$ is equal to __________.
Explanation:
$ y=m x \pm \sqrt{a^2-b^2 m^2} $
Given the hyperbola $H: \frac{y^2}{25} - \frac{x^2}{16} = 1$, the equation of the tangent to this hyperbola can be written as :
$y=mx \pm \sqrt{25 - 16m^2}$
We know that the tangents pass through the point $P(4, 1)$, which gives us the equation :
$1 = 4m \pm \sqrt{25 - 16m^2}$
Squaring both sides to get rid of the square root, we obtain :
$(4m - 1)^2 = 25 - 16m^2$
which simplifies to the quadratic equation :
$4m^2 - m - 3 = 0.$
Solving this equation, we find the roots $m_1 = 1$ and $m_2 = -\frac{3}{4}$, which are the slopes of the tangents.
Given that we are interested in the positive values of the slopes, we consider $|m_1| = 1$ and $|m_2| = \frac{3}{4}$.
The equations of the tangents are then :
1) $y = x - 3$ and
2) $y = \frac{3}{4}x - 4$.
The x-intercepts of these lines (when $y = 0$) are given by $x = \alpha = 3$ for the first line and $x = \beta = \frac{16}{3}$ for the second line.
The intersection point $Q$ of these tangents is found by solving the system of equations $y = x - 3$ and $y = \frac{3}{4}x - 4$, which gives $Q(-4, -7)$.
The square of the distance $PQ$ is then $(-4-4)^2 + (-7-1)^2 = 128$.
Therefore, $\frac{(PQ)^2}{\alpha \beta} = \frac{128}{3 \times \frac{16}{3}} = 8$
Let $\mathrm{H}_{\mathrm{n}}: \frac{x^{2}}{1+n}-\frac{y^{2}}{3+n}=1, n \in N$. Let $\mathrm{k}$ be the smallest even value of $\mathrm{n}$ such that the eccentricity of $\mathrm{H}_{\mathrm{k}}$ is a rational number. If $l$ is the length of the latus rectum of $\mathrm{H}_{\mathrm{k}}$, then $21 l$ is equal to ____________.
Explanation:
$ H_n \Rightarrow \frac{x^2}{1+n}-\frac{y^2}{3+n}=1, n \in N $
Here, $a^2=1+n$ and $b^2=3+n$
$ \begin{aligned} \operatorname{Eccentricity}(e) & =\sqrt{1+\frac{b^2}{a^2}} \\\\ & =\sqrt{1+\left(\frac{3+n}{1+n}\right)}=\sqrt{\frac{2 n+4}{n+1}}=\sqrt{\frac{2(n+2)}{n+1}} \end{aligned} $
The smallest even value for which $e \in Q$ is 48 .
$ \begin{aligned} \therefore n & =48 \\\\ \therefore e & =\sqrt{\frac{2(48+2)}{48+1}}=\frac{10}{7} \end{aligned} $
$ \begin{array}{ll} \Rightarrow a^2=n+1=49, b^2=n+3=51 \\\\ \therefore 21 l=21 \times\left(\frac{2 b^2}{a}\right)=21 \times 2 \times \frac{51}{7}=306 \end{array} $
Let the eccentricity of an ellipse $\frac{x^{2}}{a^{2}}+\frac{y^{2}}{b^{2}}=1$ is reciprocal to that of the hyperbola $2 x^{2}-2 y^{2}=1$. If the ellipse intersects the hyperbola at right angles, then square of length of the latus-rectum of the ellipse is ___________.
Explanation:
$\Rightarrow \frac{x^2}{1 / 2}-\frac{y^2}{1 / 2}=1$
Here, $a=b$
$\therefore$ Eccentricity of rectangular hyperbola is $\sqrt{2}$
$\therefore$ Eccentricity of ellipse is $\frac{1}{\sqrt{2}}$
Since, ellipse intersects the hyperbola at right angles
$\therefore$ Ellipse and the hyperbola are confocal
$\therefore$ Foci of hyperbola $=(1,0)$
$\Rightarrow$ Foci of ellipse, $a e=1$
$ \begin{array}{ll} &\Rightarrow a\left(\frac{1}{\sqrt{2}}\right)=1 \\\\ &\Rightarrow a=\sqrt{2} \\\\ &\therefore e^2=1-\frac{b^2}{a^2} \\\\ &\Rightarrow \frac{1}{2}=1-\frac{b^2}{2} \\\\ &\Rightarrow \frac{b^2}{2}=\frac{1}{2} \\\\ &\Rightarrow b^2=1 \end{array} $
$\therefore$ Length of the latus rectum $=\frac{2 b^2}{a}=\frac{2}{\sqrt{2}}=\sqrt{2}$
$\therefore$ Square of length of the latus rectum $=2$
The vertices of a hyperbola H are ($\pm$ 6, 0) and its eccentricity is ${{\sqrt 5 } \over 2}$. Let N be the normal to H at a point in the first quadrant and parallel to the line $\sqrt 2 x + y = 2\sqrt 2 $. If d is the length of the line segment of N between H and the y-axis then d$^2$ is equal to _____________.
Explanation:

$ H: \frac{x^2}{36}-\frac{y^2}{9}=1 $
equation of normal is $6 x \cos \theta+3 y \cot \theta=45$
$ \begin{aligned} & \text { slope }=-2 \sin \theta=-\sqrt{2} \\\\ & \Rightarrow \theta=\frac{\pi}{4} \end{aligned} $
Equation of normal is $\sqrt{2} x+y=15$
$P:(a \sec \theta, b \tan \theta)$
$\Rightarrow \mathrm{P}(6 \sqrt{2}, 3)$ and $\mathrm{K}(0,15)$
$ d^2=216 $
If the line $2 x+\sqrt{6} y=2$ touches the hyperbola $x^2-2 y^2=4$, then the coordinates of the point of contact are
$\left(\frac{1}{2}, \frac{1}{\sqrt{6}}\right)$
$(4,-\sqrt{6})$
$(4, \sqrt{6})$
$(-2, \sqrt{6})$
If the angle between the asymptotes of a hyperbola is $30^{\circ}$, then its eccentricity is
$\sqrt{5}-\sqrt{2}$
$\sqrt{6}-\sqrt{3}$
$\sqrt{5}-\sqrt{3}$
$\sqrt{6}-\sqrt{2}$
Let $A=(1,2), B=(2,1), C=(-1,-1)$ be three points. If $P$ is a point such that the area of the quadrilateral $P A B C$ is twice the area of the $\triangle P A B$, then the equation of the locus of $P$ is
$8 x^2-14 x y+3 y^2-18 x+22 y+7=0$
$9 x^2-12 x y+4 y^2-24 x+16 y+16=0$
$x^2+2 x y+y^2-6 x-6 y+9=0$
$x^2-4 x y+8 y-4=0$
If the equation $x+y+n=0$ represents a normal to the hyperbola $\frac{x^2}{6}-\frac{y^2}{2}=1$, then $n=$
$\pm \sqrt{3}$
$\pm 4$
$\pm \sqrt{2}$
$\pm 2$
If $y=m x+4(m>0)$ is a tangent to the hyperbola $\frac{x^2}{25}-\frac{y^2}{9}=1$, then the point of contact of this tangent is
$\left(-\frac{25}{4},-\frac{9}{4}\right)$
$\left(\frac{25}{4}, \frac{9}{4}\right)$
$(1,5)$
$\left(-\frac{1}{2}, \frac{7}{2}\right)$
$P(a \sec \theta, b \tan \theta)$ and $Q(a \sec \phi, b \tan \phi)$ are two points on the hyperbola $\frac{x^2}{a^2}-\frac{y^2}{b^2}=1$ where, $\phi+\theta=\frac{\pi}{2}$. If $(h, k)$ is the point of intersection of the normals drawn at $P$ and $Q$, then $k=$
Let the hyperbola $H: \frac{x^{2}}{a^{2}}-\frac{y^{2}}{b^{2}}=1$ pass through the point $(2 \sqrt{2},-2 \sqrt{2})$. A parabola is drawn whose focus is same as the focus of $\mathrm{H}$ with positive abscissa and the directrix of the parabola passes through the other focus of $\mathrm{H}$. If the length of the latus rectum of the parabola is e times the length of the latus rectum of $\mathrm{H}$, where e is the eccentricity of H, then which of the following points lies on the parabola?




