Q. If $M_{1}$ and $M_{2}$ are the feet of the perpendiculars from the foci $S_{1}$ and $S_{2}$ of the ellipse $\frac{x^{2}}{9} + \frac{y^{2}}{16} = 1$ on the tangent at any point $P$ on the ellipse, then $\left( S_{1}M_{1} \right)(S_{2}M_{2})$ is equal to

A) 16
B) 9
C) 4
D) 3
Explanation

(a)
We know that the product of perpendiculars drawn from two foci $S_{1}$ and $S_{2}$ of an ellipse $\frac{x^{2}}{9} + \frac{y^{2}}{16} = 1$ on the tangent at any point $P$ on the ellipse is equal to the square of the semiminor axis.
$\therefore\left( S_{1}M_{1} \right) \bullet \left( S_{2}M_{2} \right) = 16$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.

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