Circle And System Of Circles Question 358
Question: Which of the following lines is a tangent to the circle $ x^{2}+y^{2}=25 $ for all values of m
Options:
A) $ y=mx+25\sqrt{1+m^{2}} $
B) $ y=mx+5\sqrt{1+m^{2}} $
C) $ y=mx+25\sqrt{1-m^{2}} $
D) $ y=mx+5\sqrt{1-m^{2}} $
Show Answer
Answer:
Correct Answer: B
Solution:
Line $ y=mx+c $ is a tangent if $ c=\pm a\sqrt{1+m^{2}} $
$ \therefore $ $ y=mx+5\sqrt{1+m^{2}} $ .
BETA
