NCERT Class XI Mathematics - Conic Sections - Solutions
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Question : 28
Total: 71
Solution:
We have been given an equation of ellipse
+
= 1
Clearly, 36 > 16
The equation of ellipse in standard form is
+
= 1
∴a 2 = 36 ⇒ a = 6 and b 2 = 16 ⇒ b = 4
We know that
c =√ a 2 − b 2 ⇒ c = √ 36 − 16 = √ 20
∴ Coordinates of foci are (±c, 0) i.e. (±√ 20 , 0)
Coordinates of vertices are (± a, 0) i.e. (± 6, 0).
Length of major axis = 2a = 2 × 6 = 12
Length of minor axis = 2b = 2 × 4 = 8
Eccentricity (e) =
=
Length of latus rectum =
=
=
Clearly, 36 > 16
The equation of ellipse in standard form is
∴
We know that
c =
∴ Coordinates of foci are (±c, 0) i.e. (±
Coordinates of vertices are (± a, 0) i.e. (± 6, 0).
Length of major axis = 2a = 2 × 6 = 12
Length of minor axis = 2b = 2 × 4 = 8
Eccentricity (e) =
Length of latus rectum =
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