Conic Sections Question 102
Question: If $ y=mx+c $ is tangent on the ellipse $ \frac{x^{2}}{9}+\frac{y^{2}}{4}=1 $ , then the value of c is
Options:
A) 0
B) $ 3/m $
C) $ \pm \sqrt{9m^{2}+4} $
D) $ \pm 3\sqrt{1+m^{2}} $
Show Answer
Answer:
Correct Answer: C
Solution:
Here, $ a=3,b=2 $ .By formula, $ c^{2}=b^{2}+a^{2}m^{2} $
$ c^{2}=4+9m^{2} $ ; $ c=\pm \sqrt{9m^{2}+4} $ .
BETA
