Question
Two tangents are drawn from the point (−2,−1) to the parabola y2=4x. If α is the angle between those tangents then tan α=
Answer: Option A
:
A
The equation to the pair of tangents is [−y−2(x−2)]2=(1+8)(y2−4x)⇒(−2x−y+4)2=−(y2−4x)
⇒4x2+y2+16−16x−8y+4xy=9y2−36x⇒4x2+4xy−8y2+20x−8y+16=0
∴tanα=2√4+32|4−8|=2×64=3
Was this answer helpful ?
:
A
The equation to the pair of tangents is [−y−2(x−2)]2=(1+8)(y2−4x)⇒(−2x−y+4)2=−(y2−4x)
⇒4x2+y2+16−16x−8y+4xy=9y2−36x⇒4x2+4xy−8y2+20x−8y+16=0
∴tanα=2√4+32|4−8|=2×64=3
Was this answer helpful ?
More Questions on This Topic :
Latest Videos
Latest Test Papers
Submit Solution