JEE Main & Advanced Mathematics Conic Sections Question Bank Hyperbola

  • question_answer
    If the latus rectum of an hyperbola be 8 and eccentricity be \[3/\sqrt{5}\], then the equation of the hyperbola is

    A)            \[4{{x}^{2}}-5{{y}^{2}}=100\]   

    B)            \[5{{x}^{2}}-4{{y}^{2}}=100\]

    C)            \[4{{x}^{2}}+5{{y}^{2}}=100\]   

    D)            \[5{{x}^{2}}+4{{y}^{2}}=100\]

    Correct Answer: A

    Solution :

                       \[\frac{2{{b}^{2}}}{a}=8\] and \[\frac{3}{\sqrt{5}}=\sqrt{1+\frac{{{b}^{2}}}{{{a}^{2}}}}\] or \[\frac{4}{5}=\frac{{{b}^{2}}}{{{a}^{2}}}\]                    Þ \[a=5\], \[b=2\sqrt{5}\]. Hence the required equation of hyperbola is \[\frac{{{x}^{2}}}{25}-\frac{{{y}^{2}}}{20}=1\] Þ \[4{{x}^{2}}-5{{y}^{2}}=100\].


You need to login to perform this action.
You will be redirected in 3 sec spinner