CEE Kerala Engineering CEE Kerala Engineering Solved Paper-2001

  • question_answer
    If\[{{(\sqrt{3}-i)}^{50}}={{2}^{48}}(x-iy),\]then\[{{x}^{2}}+{{y}^{2}}\]is equal to:

    A)  2                            

    B)         4

    C)  8                            

    D)         16

    E)  32

    Correct Answer: D

    Solution :

    \[\because \]\[(\sqrt{3}-i)=2\left( \cos \frac{\pi }{6}-i\sin \frac{\pi }{6} \right)\] \[\therefore \]\[{{(\sqrt{3}-i)}^{50}}={{2}^{50}}{{\left( \cos \frac{\pi }{6}-i\sin \frac{\pi }{6} \right)}^{50}}\]                 \[={{2}^{50}}\left( \cos \frac{\pi }{3}-i\sin \frac{\pi }{3} \right)\]                 \[={{2}^{50}}\left( \frac{1}{2}-i\frac{\sqrt{3}}{2} \right)\]               But\[{{(\sqrt{3}-i)}^{50}}={{2}^{48(x+iy)}}\] \[x=2\]and \[y=2\sqrt{3}\] \[\therefore \]  \[{{x}^{2}}+{{y}^{2}}=4+12=16\]


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