JEE Main 2018 — Application Of Derivatives Question with Solution
From: JEE Main 2018 (Online) 15th April Morning Slot
Question
If is one of the angles between the normals to the ellipse, x2 + 3y2 = 9 at the points (3 cos , ) and ( 3 sin , ); then is equal to :
Choose an option
Show full solutionCorrect option: A
Correct answer
A
Step-by-step explanation
Since, x2 + 3y2 = 9
2x + 6y = 0
=
Slope of normal is =
= = = m1
&
= = = m2
As, is the angle between the normals to the given ellipse then
tan =
= =
So, tan =
=
2x + 6y = 0
=
Slope of normal is =
= = = m1
&
= = = m2
As, is the angle between the normals to the given ellipse then
tan =
= =
So, tan =
=
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This is a previous-year question from JEE Main 2018, covering the Application Of Derivatives chapter of Mathematics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.