Circle And System Of Circles Question 235
Question: If the line $ lx+my+n=0 $ be a tangent to the circle $ {{(x-h)}^{2}}+{{(y-k)}^{2}}=a^{2}, $ then
Options:
A) $ hl+km+n=a^{2}(l^{2}+m^{2}) $
B) $ {{(hl+km+n)}^{2}}=a(l^{2}+m^{2}) $
C) $ {{(hl+km+n)}^{2}}=a^{2}(l^{2}+m^{2}) $
D) None of these
Show Answer
Answer:
Correct Answer: C
Solution:
According to the condition, $ a=\frac{hl+mk+n}{\sqrt{l^{2}+m^{2}}} $
$ \Rightarrow {{(hl+km+n)}^{2}}=a^{2}(l^{2}+m^{2}) $ .
BETA
