Circle And System Of Circles Question 19
Question: Locus of the points from which perpendicular tangent can be drawn to the circle $ x^{2}+y^{2}=a^{2} $ , is
Options:
A) A circle passing through origin
B) A circle of radius 2a
C) A concentric circle of radius $ a\sqrt{2} $
D) None of these
Show Answer
Answer:
Correct Answer: C
Solution:
Required locus is $ SS_1=T^{2} $
$ (x^{2}+y^{2}-a^{2})(h^{2}+k^{2}-a^{2})={{(hx+ky-a^{2})}^{2}} $
But as given, coefficient of $ x^{2}+ $ coefficient of $ y^{2}=0 $
$ \Rightarrow $ $ h^{2}+k^{2}=2a^{2} $ .
BETA
