Question bank/JEE Main/Mathematics

JEE MainMathematicsModerateEllipse

Tangents are drawn to the ellipse x2+2y2=2x^{2} + 2y^{2} = 2. The
locus of the midpoint of the intercept made by tangents between the axes

is
12x2+1ky2=1\frac{1}{2x^{2}} + \frac{1}{ky^{2}} = 1 then 4k is
fcUnqvksa dk fcUnqiFk

12x2+1ky2=1\frac{1}{2x^{2}} + \frac{1}{ky^{2}} = 1gS rc 4k

Show answer and solution
[IMAGE] Consider any point P(2cosθ,sinθ)P(\sqrt{2}cos\theta,sin\theta)
Tangent at this point is
2cosθx+2sinθy=2\sqrt{2}cos\theta x + 2sin\theta y = 2
Now it intersect at x-axis at
(2secθ,0)(\sqrt{2}sec\theta,0) and y-axis at
(0,cosecθ)(0,cosec\theta)
Now find its midpoint and eliminate
θ\theta by squaring and adding.
[IMAGE] ekuk fd fcUnqP(√2 cos 𝜃, sin 𝜃)

bl fcUnq ij √2 cos 𝜃 𝑥 + 2 sin 𝜃 𝑦 = 2

vc

vc bl fcUnq Kkr dhft, rFkk𝜃


Source: Grass-G / M-26 Mathematics Paper 1 15 Jan.docx

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