Conic Sections Question 512
Question: The equation of latus rectum of a parabola is $ x+y=8 $ and the equation of the tangent at the vertex is $ x+y=12 $ , then length of the latus rectum is
[MP PET 2002]
Options:
A) $ 4\sqrt{2} $
B) $ 2\sqrt{2} $
C) 8
D) $ 8\sqrt{2} $
Show Answer
Answer:
Correct Answer: D
Solution:
Clearly; $ a=| \frac{-8}{\sqrt{1+1}} |-| \frac{-12}{\sqrt{1+1}} |=\frac{4}{\sqrt{2}} $
Length of latus rectum = 4a $ =4\times \frac{4}{\sqrt{2}}=8\sqrt{2} $ .
BETA
