RAJASTHAN ­ PET Rajasthan PET Solved Paper-2005

  • question_answer
    In the interval\[0<x<2\pi ,\]the solution of \[(2\text{ }cos\text{ }x-1)(3+2\text{ }cos\text{ }x)=0\]is

    A)  \[\left\{ \frac{\pi }{3} \right\}\]

    B)  \[\left\{ \frac{\pi }{3},\frac{5\pi }{3} \right\}\]

    C)  \[\left\{ \frac{\pi }{3},\frac{5\pi }{3},{{\cos }^{-1}}\left( -\frac{3}{2} \right) \right\}\]

    D)  None of the above

    Correct Answer: B

    Solution :

     Given, \[(2\text{ }cos\text{ }x-1)(3+2\text{ }cos\text{ }x)=0\] \[\Rightarrow \] \[\cos x=\frac{1}{2},\cos x\ne -\frac{3}{2}\] \[\Rightarrow \] \[x=\frac{\pi }{3},\frac{5\pi }{3}\in (0,2\pi )\]


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