Circle And System Of Circles Question 357
Question: The line $ y=x+c $ will intersect the circle $ x^{2}+y^{2}=1 $ in two coincident points, if
Options:
A) $ c=\sqrt{2} $
B) $ c=-\sqrt{2} $
C) $ c=\pm \sqrt{2} $
D) None of these
Show Answer
Answer:
Correct Answer: C
Solution:
$ y=x+c $ intersects at two coincident points, i.e. it is a tangent, therefore $ c^{2}=1(1+1)\Rightarrow c=\pm \sqrt{2} $ .
BETA
