The pole of the straight line $x+4 y=4$ with respect to the ellipse $x^2+4 y^2=4$ is

The pole of the straight line $x+4 y=4$ with respect to the ellipse $x^2+4 y^2=4$ is
  1. $(1,1)$
  2. $(1,4)$
  3. $(4,1)$
  4. $(4,4)$

Solution

Equation of line is $x+4 y-4=0$ $ l=1, m=4, n=-4 $ and equation of ellipse is $ \begin{aligned} \Rightarrow & x^2+4 y^2=4 \\ \Rightarrow & \frac{x^2}{4}+\frac{y^2}{1}=1 \\ & a^2=4, b^2=1 \end{aligned} $ Pole of the straight line with respect to ellipse $ =\left(\frac{-a^2 l}{n}, \frac{-b^2 m}{n}\right)=\left(\frac{-4.1}{-4}, \frac{-1.4}{-4}\right)=(1,1) $

Asked in: AP EAMCET 2002

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