A line is drawn from A(-2,0) to intersect the curve y2=4x at P and Q in the first quadrant such that 1AP+1AQ<14 . Then the slope of the line is always
see full answer
Your Exam Success, Personally Taken Care Of
1:1 expert mentors customize learning to your strength and weaknesses – so you score higher in school , IIT JEE and NEET entrance exams.
An Intiative by Sri Chaitanya
a
<13
b
>13
c
>2
d
>3
answer is D.
(Unlock A.I Detailed Solution for FREE)
Best Courses for You
JEE
NEET
Foundation JEE
Foundation NEET
CBSE
Detailed Solution
Let any point at a distance r from A on the parabola is (-2+rcosθ, rsinθ), P lies on y2=4x ,⇒r2sin2θ =4(-2+rcos θ ), r2sin2θ -4rcosθ+8=0Let P and Q be distances r1 and r2 from A, then r1+r2=4cosθsin2θ, r1r2=8sin2θ1AP+1AQ=1r1+1r2=r1+r2r1r2=cosθ2 Given 1AP+1AQ<14cosθ2<14⇒cosθ<12⇒tanθ>3