NCERT Class XI Mathematics - Conic Sections - Solutions
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Question : 31
Total: 71
Solution:
Given equation of ellipse is
+
= 1
Clearly, 100 > 25
The equation of ellipse in standard form is
+
= 1
∴a 2 = 100 ⇒ a = 10 and b 2 = 25 ⇒ b = 5
We know that c =√ a 2 − b 2 ⇒ c = √ 100 − 25 = √ 75 = 5 √ 3
∴ Coordinates of foci are (0, ±c) i.e. (0, ± 5√ 3 )
Coordinates of vertices are (0, ±a) i.e. (0, ±10).
Length of major axis = 2a = 2 × 10 = 20
Length of minor axis = 2b = 2 × 5 = 10
Eccentricity (e) =
=
=
Length of latus rectum =
=
= 5.
Clearly, 100 > 25
The equation of ellipse in standard form is
∴
We know that c =
∴ Coordinates of foci are (0, ±c) i.e. (0, ± 5
Coordinates of vertices are (0, ±a) i.e. (0, ±10).
Length of major axis = 2a = 2 × 10 = 20
Length of minor axis = 2b = 2 × 5 = 10
Eccentricity (e) =
Length of latus rectum =
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