Circle And System Of Circles Question 285
Question: If P is a point such that the ratio of the squares of the lengths of the tangents from P to the circles $ x^{2}+y^{2}+2x-4y-20=0 $ and $ x^{2}+y^{2}-4x+2y-44=0 $ is 2 : 3, then the locus of P is a circle with centre
[EAMCET 2003]
Options:
A) (7, - 8)
B) (- 7, 8)
C) (7, 8)
D) (- 7, - 8)
Show Answer
Answer:
Correct Answer: B
Solution:
$ \frac{x^{2}+y^{2}+2x-4y-20}{x^{2}+y^{2}-4x+2y-44}=\frac{2}{3} $
$ \Rightarrow $ $ x^{2}+y^{2}+14x-16y+28=0 $ , \Centre = $ (-7,,8) $ .
BETA
