NCERT Class XI Mathematics - Conic Sections - Solutions

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Question : 48
Total: 71
x2
16
−
y2
9
= 1
Solution:  
Given equation of hyperbola is
x2
16
−
y2
9
= 1 which is of the form
x2
a2
−
y2
b2
= 1.
The foci and vertices of the hyperbola lie on x-axis.
Now, a2 = 16 ⇒ a = 4 and b2 = 9 ⇒ b = 3
Also, c2 = a2+b2 = 16 + 9 = 25 ⇒ c = 5
∴ Coordinates of foci are (± c, 0) i.e. (± 5, 0)
Coordinates of vertices are (± a, 0) i.e. (± 4, 0)
Eccentricity (e) =
c
a
=
5
4

Length of latus rectum =
2b2
a
=
2×9
4
=
9
2
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