Pair Of Straight Lines Question 115

Question: The locus of the point $ P(x,y) $ satisfying the relation $ \sqrt{{{(x-3)}^{2}}+{{(y-1)}^{2}}}+\sqrt{{{(x+3)}^{2}}+{{(y-1)}^{2}}}=6 $ is

[Orissa JEE 2002]

Options:

A) Straight line

B) Pair of straight lines

C) Circle

D) Ellipse

Show Answer

Answer:

Correct Answer: B

Solution:

$ \sqrt{{{(x-3)}^{2}}+{{(y-1)}^{2}}}+\sqrt{{{(x+3)}^{2}}+{{(y-1)}^{2}}}=6 $

$ \sqrt{{{(x-3)}^{2}}+{{(y-1)}^{2}}}=6-\sqrt{{{(x+3)}^{2}}+{{(y-1)}^{2}}} $

Squaring both sides.

We get, $ 12x+36=12\sqrt{{{(x+3)}^{2}}+{{(y-1)}^{2}}} $

Again squaring we get the given equation is pair of straight lines.