JEE Main & Advanced Sample Paper JEE Main Sample Paper-45

  • question_answer
    Direction: For the following questions, choose the correct answers from the codes [a], [b], [c] and [d] defined as follows.
    Consider the principal argument of a complex number z is 9.
    Statement I Principal argument of \[{{z}^{2}}\] is \[2\theta \].
    Statement II\[\arg \,({{z}^{2}})=2\,\arg \,(z)\].

    A)  Statement I is true. Statement II is also true and Statement n is the correct explanation of Statement I.

    B)  Statement I is true. Statement II is also true and Statement n is not the correct explanation of Statement I.

    C)  Statement I is true. Statement II is false.

    D)  Statement I is false. Statement II is true.

    Correct Answer: D

    Solution :

     Statement I If principal argument of z is \[\theta \], then argument of \[{{z}^{2}}\] will be \[2\theta \] \[\therefore \] Principal argument of \[z=\pi -\frac{\pi }{4}=\frac{3\pi }{4}\] Argument \[({{z}^{2}})=2\times \frac{3\pi }{4}=\frac{3\pi }{2}\] But principal argument \[({{z}^{2}})=-\frac{\pi }{2}\]


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