JAMIA MILLIA ISLAMIA Jamia Millia Islamia Solved Paper-2015

  • question_answer
    If \[x=0\]and\[\underset{x\to 1}{\mathop{\lim }}\,\frac{\tan ({{x}^{2}}-1)}{x-1}\], then abc equals

    A) \[\frac{1}{2}\]                                   

    B) \[\frac{-1}{2}\]

    C) \[y={{x}^{3}}-3{{x}^{2}}-9x+5\]                                 

    D) \[(1,2,\sqrt{3})\]

    Correct Answer: A

    Solution :

    We have, \[a=lo{{g}_{24}}12,b=lo{{g}_{36}}24,c={{\log }_{48}}36\] \[abc=1o{{g}_{24}}12.{{\log }_{36}}24.{{\log }_{48}}36\] \[abc=1o{{g}_{48}}12\]                 Also, \[bc={{\log }_{36}}24.{{\log }_{48}}36={{\log }_{48}}24\]                 \[\therefore \]  \[abc-2bc={{\log }_{48}}12-2{{\log }_{48}}24\]                                 \[={{\log }_{48}}12-{{\log }_{48}}{{24}^{2}}\] \[={{\log }_{48}}\left( \frac{12}{24\times 24} \right)\]                                 \[={{\log }_{48}}\left( \frac{1}{48} \right)=0-{{\log }_{48}}48=-1\]                 \[\therefore \]  \[abc=2bc-1\]


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