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Let $F_1\left(x_1, 0\right)$ and $F_2\left(x_2, 0\right)$, for $x_1<0$ and $x_2>0$, be the foci of the ellipse $\frac{x^2}{9}+\frac{y^2}{8}=1$. Suppose a parabola having vertex at the origin and focus at $F_2$ intersects the ellipse at point $M$ in the first quadrant and at point $N$ in the fourth quadrant.
($1$)The orthocentre of the triangle $F_1 M N$ is
($A$) $\left(-\frac{9}{10}, 0\right)$ ($B$) $\left(\frac{2}{3}, 0\right)$ ($C$) $\left(\frac{9}{10}, 0\right)$ ($D$) $\left(\frac{2}{3}, \sqrt{6}\right)$
($2$) If the tangents to the ellipse at $M$ and $N$ meet at $R$ and the normal to the parabola at $M$ meets the $x$-axis at $Q$, then the ratio of area of the triangle $M Q R$ to area of the quadrilateral $M F_{\mathrm{I}} N F_2$ is
($A$) $3: 4$ ($B$) $4: 5$ ($C$) $5: 8$ ($D$) $2: 3$
Givan the answer qestion ($1$) and ($2$)
$A,B$
$A,D$
$A,C$
$A,B,D$
Solution

$1.$ The correct option is $A \left(-\frac{9}{10}, 0\right)$
$Image$
Equation of the ellipse:
$\frac{x^2}{9}+\frac{y^2}{8}=1$
$a=3, b=2 \sqrt{2}$
Hence, eccentricity is
$e^2=1-\frac{b^2}{a^2}=\frac{1}{9}$
$\Rightarrow e=\frac{1}{3}$
So, foci of ellipse are ( $\pm 1,0$ )
Equation of the parabola having vertex $(0,0)$ and focus $(1,0)$ is
$y^2=4 x$
From equations $(1)$ and $(2)$, we get
$\frac{x^2}{9}+\frac{4 x}{8}=1$
$\Rightarrow 2 x^2+9 x-18=0$
$\Rightarrow(2 x-3)(x+6)=0$
$\Rightarrow x=\frac{3}{2} \quad[\because x=-6 \rightarrow \text { not possible }]$
$\therefore M \equiv\left(\frac{3}{2} \cdot \sqrt{6}\right), \quad N \equiv\left(\frac{3}{2}-\sqrt{6}\right)$
Equation of altitude from vertex $M\left(\frac{3}{2}, \sqrt{6}\right)$ is
$(y-\sqrt{6})=\frac{5}{2 \sqrt{6}}\left(x-\frac{3}{2}\right)$
$\because x$-axis is altitude drawn through vertex $F_1$
$\therefore$ orthocentre lies on the $x$-axis,
$\therefore 0-\sqrt{6}=\frac{5}{2 \sqrt{6}}\left(x-\frac{3}{2}\right)$
$\Rightarrow x =-\frac{9}{10}$
Hence, the orthocentre of $\triangle F_1 M N$ is
$\left(-\frac{9}{10} 0\right)$
$2.$ $Image$ Equation of tangent at point $M\left(\frac{3}{2}, \sqrt{6}\right)$ to the ellipse is $\frac{x\left(\frac{3}{2}\right)}{9}+\frac{y \sqrt{6}}{8}=1$ Put $y=0 \Rightarrow R$ is $(6,0) \quad[\because R$ lies on $x$-axis $)$
Equation of the normal to the parabola at point $M\left(\frac{3}{2} \sqrt{6}\right)$ is
$y-\sqrt{6}=\frac{-\sqrt{6}}{2}\left(x-\frac{3}{2}\right)$
Put $y=0 \Rightarrow Q$ is $\left(\frac{7}{2}, 0\right) \quad[\because Q$ lies on $x$-axis $)$
Area of $\triangle M Q R=\frac{1}{2} \times \sqrt{6} \times \frac{5}{2}=\frac{5 \sqrt{6}}{4}$
Area of quadrilateral $MF _1 NF _2$
$=$ Area of $\triangle M F_1 F_2+$ Area of $\triangle N F_1 F_2$
$=\sqrt{6}+\sqrt{6}=2 \sqrt{6}$
$\therefore$ Area of $\triangle M Q R$ : Area of quadrilateral $M F_1 N F_2=5: 8$