Questions
The sum of the squares of the
perpendiculars on any tangent to the ellipse
from two points on the minor
axis each at a distance from the centre is
detailed solution
Correct option is A
The eccentricity e of the given ellipse is given by g2=1−b2/a2⇒a2−b2=a2e2 . So the point on the minoraxis, i.e. y-axis at a distance a2−b2 from the centre (0, 0) of the ellipse are (0, ± ae). The equation of the tangent at any point (a cos θ, b sin θ) on the ellipse is xacosθ+ybsinθ=1 So the required sum is aesinθb−1cos2θa2+sin2θb22+−aesinθb−1cos2θa2+sin2θb22=(aesinθ−b)2+(aesinθ+b)2b2cos2θ+a2sin2θ×a2=2a2a2e2sin2θ+b2b2cos2θ+a2sin2θ =2a2a2−b2sin2θ+b2b2cos2θ+a2sin2θ=2a2Talk to our academic expert!
Similar Questions
Let P be any point on the directrix of an ellipse of eccentricity e. S be the corresponding focus and C the centre of the ellipse. The line PC meets the ellipse at A. the angle between PS and tangent at A is , then is not equal to
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