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NCERT Class XI Mathematics - Conic Sections - Solutions

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Question : 51 of 71
Marks: +1, -0
16x29y216x^2 - 9y^2 = 576
Solution:  
Given equation of hyperbola is 16x29y216x^2 - 9y^2 = 576
i.e., 16x25769y2576\frac{16x^2}{576} - \frac{9y^2}{576} = 1 ⇒ x236y264\frac{x^2}{36} - \frac{y^2}{64} = 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 = 36 ⇒ a = 6 and b2b^2 = 64 ⇒ b = 8
Also, c2c^2 = a2+b2a^2 + b^2 = 36 + 64 = 100 ⇒ c = 10
∴ Coordinates of foci are (± c, 0) i.e, (±10, 0)
∴ Coordinates of vertices are (± a, 0) i.e. (± 6, 0)
Eccentricity (e) = ca\frac{c}{a} = 106\frac{10}{6} = 53\frac{5}{3}
Length of latus rectum = 2b2a\frac{2b^2}{a} = 2×646\frac{2 \times 64}{6} = 643\frac{64}{3}.
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