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NCERT Class XI Mathematics - Conic Sections - Solutions

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Question : 48 of 71
Marks: +1, -0
x216y29\frac{x^2}{16}-\frac{y^2}{9} = 1
Solution:  
Given equation of hyperbola is
x216y29\frac{x^2}{16}-\frac{y^2}{9} = 1 which is of the form x2a2y2b2\frac{x^2}{a^2}-\frac{y^2}{b^2} = 1.
The foci and vertices of the hyperbola lie on x-axis.
Now, a2a^2 = 16 ⇒ a = 4 and b2 = 9 ⇒ b = 3
Also, c2c^2 = a2+b2a^2 + b^2 = 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) = ca\frac{c}{a} = 54\frac{5}{4}
Length of latus rectum = 2b2a\frac{2b^2}{a} = 2×94\frac{2 \times 9}{4} = 92\frac{9}{2}
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