Q. The radical axis of the coaxial system of circles with limiting points (1, 2) and $( - 2,\ 1)$is
A) $x + 3y = 0$
B) $3x + y = 0$
C) $2x + 3y = 0$
D) $3x + 2y = 0$
Explanation
(b)
Given limiting points are (1, 2), $( - 2,\ 1)$
The mid point is $\left( - \frac{1}{2},\frac{3}{2} \right)$
Now, slope$= \frac{1 - 2}{- 2 - 1} = \frac{1}{3}$
$\therefore$ required equation, $y - \frac{3}{2} = - 3\left( x + \frac{1}{2} \right)$
$\Rightarrow \ \ 3x + y = 0$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.