Question

lf $(2,-1)$ and $(-6,-7)$ are the limiting points of a coaxial system then the diameter of the smallest circle belonging to the conjugate coaxial system is

• A. $5$
• B. $20$
• C. $10$
• D. $\frac{5}{2}$

Answer 1

The correct option is C $10$

Circle of conjugate system with minimum radius will be the circle having
limiting points as diameter.
Thus required diameter $=\sqrt{(2+6{)}^2+(-1+7{)}^2}=10$