JEE Main & Advanced Mathematics Complex Numbers and Quadratic Equations Question Bank Self Evaluation Test - Complex Numbers and Quadratic Equations

  • question_answer
    If \[z=\frac{\pi }{4}{{(1+i)}^{4}}\left( \frac{1-\sqrt{\pi }i}{\sqrt{\pi }+i}+\frac{\sqrt{\pi }-i}{1+\sqrt{\pi }i} \right),\] then \[\left( \frac{|z|}{am{{p}^{(z)}}} \right)\] equals

    A) 1         

    B) \[\pi \]    

    C) \[3\pi \]             

    D) 4

    Correct Answer: D

    Solution :

    \[z=\frac{\pi }{4}{{(1+i)}^{4}}\left( \frac{1-\sqrt{\pi }i}{\sqrt{\pi }+i}+\frac{\sqrt{\pi }-i}{1+\sqrt{\pi }i} \right)\] \[=\frac{\pi }{4}{{(1+i)}^{4}}\left[ \frac{1+\pi +\pi +1}{(\sqrt{\pi }+i)(1+\sqrt{\pi }i)} \right]=\frac{\pi }{4}{{(1+i)}^{4}}\frac{2}{i}\] \[=\frac{\pi }{4}{{(2i)}^{2}}\frac{2}{i}=2\pi i\,\,\,\therefore \left( \frac{|z|}{amp(z)} \right)=\frac{2\pi }{\frac{\pi }{2}}=4\]


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