Circle And System Of Circles Question 39
Question: If a circle, whose centre is (-1, 1) touches the straight line $ x+2y+12=0 $ , then the coordinates of the point of contact are
[MP PET 1998]
Options:
A) $ 4y=9 $
B) $ y=3 $
C) $ y=-3 $
D) $ x=3 $
Show Answer
Answer:
Correct Answer: B
Solution:
$ S_1=x^{2}+y^{2}-12y+27=0 $
$ S_2=x^{2}+y^{2}-9=0 $ The equation of common tangent is $ S_1-S_2=0\Rightarrow -12y+36=0\Rightarrow y=3 $ .
BETA
