Question

The point of contact of x-2y+3 =0 with the ellipse

x² + 2y² = 3 is

• A. (1,1)
• B. (1,-1)
• C. (-1,1)
• D. (-1,-1)

Answer 1

Answer: (C)

(-1,1)

Answer 2

The point of contact of lx+my+n =0 with the ellipse

$\frac{x^{2}}{a^{2}} + \frac{y^{2}}{b^{2}} = 1$ is $\left( \frac{- a^{2}\mathcal{l}}{n},\mspace{6mu}\frac{- b^{2}m}{n} \right)$ Given l = 1, m = -2,

n = 3, a² = 3, b² = 3/2

∴ Point of contact = (-1, 1)