NCERT Class XI Mathematics - Conic Sections - Solutions
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Question : 36
Total: 71
Solution:
Given equation of ellipse is 4 x 2 + 9 y 2 = 36
i.e.,
= 1 ⇒
+
= 1
Clearly, 9 > 4 ⇒a 2 = 9 and b 2 = 4
The equation of ellipse in standard form is
+
= 1
∴a 2 = 9 ⇒ a = 3 and b 2 = 4 ⇒ b = 2
We know that c =√ a 2 − b 2 ⇒ c = √ 9 − 4 = √ 5
∴ Coordinates of foci are (±c, 0) i.e. (±√ 5 , 0)
Coordinates of vertices are (±a, 0) i.e. (±3, 0).
Length of major axis = 2a = 2 × 3 = 6
Length of minor axis = 2b = 2 × 2 = 4
Eccentricity (e) =
=
Length of latus rectum =
=
=
i.e.,
Clearly, 9 > 4 ⇒
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. (±3, 0).
Length of major axis = 2a = 2 × 3 = 6
Length of minor axis = 2b = 2 × 2 = 4
Eccentricity (e) =
Length of latus rectum =
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