Circle And System Of Circles Question 24
Question: If the line $ y=mx+c $ be a tangent to the circle $ x^{2}+y^{2}=a^{2} $ , then the point of contact is
Options:
A) $ ( \frac{-a^{2}}{c},a^{2} ) $
B) $ ( \frac{a^{2}}{c},\frac{-a^{2}m}{c} ) $
C) $ ( \frac{-a^{2}m}{c},\frac{a^{2}}{c} ) $
D) $ ( \frac{-a^{2}c}{m},\frac{a^{2}}{m} ) $
Show Answer
Answer:
Correct Answer: C
Solution:
Find points of intersection by solving simultaneously
Solving for x and y from $ y=mx+c $ and $ x^{2}+y^{2}=a^{2} $ which comes out as $ ( -\frac{a^{2}m}{c^{2}+m^{2}},\ \frac{a^{2}c}{c^{2}+m^{2}} ) $ .
BETA
