Circle And System Of Circles Question 93
Question: The equation of the chord of the circle $ x^{2}+y^{2}=a^{2} $ having $ (x_1,y_1) $ as its mid-point is
[IIT 1983; MP PET 1986; Pb. CET 2003]
Options:
A) $ xy_1+yx_1=a^{2} $
B) $ x_1+y_1=a $
C) $ xx_1+yy_1=x_1^{2}+y_1^{2} $
D) $ xx_1+yy_1=a^{2} $
Show Answer
Answer:
Correct Answer: C
Solution:
$ T=S_1 $ is the equation of desired chord,
Hence $ xx_1+yy_1-a^{2}=x_1^{2}+y_1^{2}-a^{2}\Rightarrow xx_1+yy_1=x_1^{2}+y_1^{2} $ .
BETA
