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10-2. Parabola, Ellipse, Hyperbola
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यदि अतिपरवलयों $\frac{{{x^2}}}{{{a^2}}} - \frac{{{y^2}}}{{{b^2}}} = 1$ तथा $\frac{{{y^2}}}{{{b^2}}} - \frac{{{x^2}}}{{{a^2}}} = 1$ की उत्केन्द्रतायें क्रमश: e तथा ${e_1}$ हों, तो $\frac{1}{{{e^2}}} + \frac{1}{{e_1^2}} = $
A
$1$
B
$2$
C
$3$
D
इनमें से कोई नहीं
Solution
(a) $e = \sqrt {1 + \frac{{{b^2}}}{{{a^2}}}} $
${e^2} = \frac{{{a^2} + {b^2}}}{{{a^2}}}$
${e_1} = \sqrt {1 + \frac{{{a^2}}}{{{b^2}}}} $
$e_1^2 = \frac{{{b^2} + {a^2}}}{{{b^2}}}$
$\frac{1}{{e_1^2}} + \frac{1}{{{e^2}}} = 1$.
Standard 11
Mathematics