NEET Sample Paper NEET Sample Test Paper-27

  • question_answer
    The function \[F(t)=\sin \omega t+\cos \omega t\] corresponds a:

    A)  Simple harmonic function

    B)  Periodic function

    C)  Cylindrical functions

    D)  None of the above.

    Correct Answer: A

    Solution :

    Here : function is \[F(t)=(\sin \omega t+\cos \omega t)\] It can be written as follows: \[F(t)=\sqrt{2}\,\,\left( \frac{1}{\sqrt{2}}\sin \omega t+\frac{1}{\sqrt{2}}\cos \omega t \right)\] \[\Rightarrow \] \[F(t)=\sqrt{2}\left( \cos \frac{\pi }{4}\sin \omega t+\sin \frac{\pi }{4}\cos \omega t \right)\]             \[\left( \because \,\,\sin \frac{\pi }{4}=\cos \frac{\pi }{4}=\frac{1}{\sqrt{2}} \right)\] \[\Rightarrow \]            \[F(t)=\sqrt{2}\sin \left( \omega t+\frac{\pi }{4} \right)\] \[[\because \,\,\sin A\,\cos B+\cos A\operatorname{sinB}=sin(A+B)]\]             \[=\sqrt{2}\sin \left( \omega t+\frac{\pi }{4}+2\pi  \right)\] \[(\because \,\,\sin \theta =\sin (\theta +2\pi ))\]             \[=\sqrt{2}\,\sin \,\left[ \omega \left( t+\frac{2\pi }{\omega } \right)+\frac{\pi }{4} \right]\] This represent a simple harmonic motion with time period\[\frac{2\pi }{\omega }\].


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