11th Class Mathematics Sample Paper Mathematics Olympiad - Sample Paper-5

  • question_answer
    \[\sqrt{i}-\sqrt{-i}\] is equal to

    A) (a) \[i\sqrt{2}\]                          

    B) (b) \[\frac{i}{i\sqrt{2}}\]           

    C) (c) 0                             

    D) (d) \[-i\sqrt{2}\]

    Correct Answer: A

    Solution :

    [a] \[\because i=0+1\] \[=\frac{1}{2}\left( 0+2i \right)=\frac{1}{2}{{\left( 1-i \right)}^{2}}\] \[\therefore \sqrt{i}=\pm \frac{1}{\sqrt{2}}(1+i)\]Taking positive sign, we have \[\sqrt{-i}=\frac{1}{\sqrt{2}}(1+i)\And \sqrt{i}-\sqrt{-i}=\frac{1}{\sqrt{2}}(1+i-1+i)\] \[=\frac{2i}{\sqrt{2}}=\sqrt{2}i\]Hence, option [a] is correct.


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