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Grade 11Analytical Geometry

The equation x²/(10-a)+y²(4-a)=1 represents an ellipse if 1)a104 3)4

Profile image of Vignesh
9 Years agoGrade 11
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1 Answer

Profile image of Vikas TU
ApprovedApproved Tutor Answer9 Years ago
 
For ellipse its eccentricity should lie between 0 to 1.
1 –  (a-4)^2/(a-10)^2  less than 1
and 
1 –  (a-4)^2/(a-10)^2  greater than zero.
On solving separtely with each interval U would get,
 (a-4)^2/(a-10)^2 less than 1
or
(a-7) less than 0
or a is less than 7.
Hence 3) option a = 4 which is less than 7 .