JEE Main & Advanced Sample Paper JEE Main Sample Paper-3

  • question_answer
    Statement -1: The period of \[f(x)=\sin 2x\cos [2x]-\cos 2x\sin [2x]\]is \[\frac{1}{2}\]
    Statement-2: The period of x-[x] is 1

    A)  Statement-1 is true, Statement-2 is true; Statement-2 is a correct explanation for Statement-1.

    B)  Statement-1 is true, Statement-2 is true; Statement-2 is not a correct explanation for Statement-1.

    C)  Statement-1 is true, Statement-2 is false.

    D)  Statement-1 is false, Statement-2 is true.

    Correct Answer: A

    Solution :

     \[f(x)=x-[x]\] \[f(x+1)=x+1-([x]+1)=x-[x]\] Period of x-[x] is 1 f(x)=sin(2x-[2x]) \[f\left( x+\frac{1}{2} \right)=\sin \left( 2\left( x+\frac{1}{2} \right)-\left[ 2\left( x+\frac{1}{2} \right) \right] \right)\] \[=\sin (2x+1-[2x]-1)=\sin (2x-[2x])\] Period is\[\frac{1}{2}.\]


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