Circle And System Of Circles Question 236

Question: The locus of the middle points of chords of the circle $ x^{2}+y^{2}-2x-6y-10=0 $ which passes through the origin, is

[Roorkee 1989]

Options:

A) $ x^{2}+y^{2}+x+3y=0 $

B) $ x^{2}+y^{2}-x+3y=0 $

C) $ x^{2}+y^{2}+x-3y=0 $

D) $ x^{2}+y^{2}-x-3y=0 $

Show Answer

Answer:

Correct Answer: D

Solution:

Let the midpoint of chord be (h, k), then its equation is $ T=S_1 $ i.e., $ {{(p-x)}^{2}}=4qy $

$ =h^{2}+k^{2}-2h-6k-10 $

Since it passes through the origin, therefore $ h^{2}+k^{2}-h-3k=0 $ or locus is $ x^{2}+y^{2}-x-3y=0 $ .