JCECE Engineering JCECE Engineering Solved Paper-2010

  • question_answer
    The sum of the series \[{{\log }_{4}}2-{{\log }_{8}}2+{{\log }_{16}}2-....\infty \], is

    A) \[{{e}^{2}}\]                                      

    B) \[{{\log }_{e}}2+1\]

    C) \[{{\log }_{e}}2-1\]                         

    D) \[1-{{\log }_{e}}2\]

    Correct Answer: D

    Solution :

    We have, the given series                 \[{{\log }_{4}}2-{{\log }_{8}}2+{{\log }_{16}}2-...\infty \]                 \[=\frac{\log 2}{\log 4}-\frac{\log 2}{\log 8}+\frac{\log 2}{\log 16}-....\infty \]                 \[=\frac{\log 2}{2\log 2}-\frac{\log 2}{3\log 2}+\frac{\log 2}{4\log 2}-...\infty \]                 \[=\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-...\infty \]                 \[=1-1+\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-...\infty \]                 \[1-\left[ 1-\frac{1}{2}+\frac{1}{3}-\frac{1}{4}+...\infty  \right]\]                 \[=1-{{\log }_{e}}2\]


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