CEE Kerala Engineering CEE Kerala Engineering Solved Paper-2006

  • question_answer
    \[\int{\left( \frac{\sin 2x}{\sin 3x\sin 5x} \right)}dx\]is equal to:

    A)  \[\frac{1}{5}{{\log }_{e}}|\sin 5x|-\frac{1}{3}{{\log }_{e}}|\sin 3x|+c\]

    B)  \[\frac{1}{3}{{\log }_{e}}|\sin 3x|-\frac{1}{5}{{\log }_{e}}|\sin 5x|+c\]

    C)  \[\frac{1}{3}{{\log }_{e}}|\sin 3x|+\frac{1}{5}{{\log }_{e}}|\sin 5x|+c\]

    D)  \[-\frac{1}{2}\cos 2x+\frac{1}{3}{{\log }_{e}}|\sin 3x|\] \[+\frac{1}{5}{{\log }_{e}}|sin5x|+c\]

    E)  \[-\frac{1}{2}\cos 2x-\frac{1}{3}{{\log }_{e}}|\sin 3x|\]\[-\frac{1}{5}{{\log }_{e}}|\sin 5x|+c\]

    Correct Answer: B

    Solution :

    \[\int{\frac{\sin 2x}{\sin 3x\sin 5x}}dx=\int{\frac{\sin (5x-3x)}{\sin 3x\sin 5x}}dx\] \[=\int{\frac{\sin 5x\cos 3x-\cos 5x\sin 3x}{\sin 3x\sin 5x}}dx\] \[=\int{(\cot 3x-\cot 5x)}dx\] \[=\frac{1}{3}\log |\sin 3x|-\frac{1}{5}\log |\sin 5x|+c\]


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