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

  • question_answer
    If \[|z-2|=\min \{|z-1|,|z-5|\},\] where z is a complex number, then

    A) \[\operatorname{Re}(z)=\frac{3}{2}\]

    B) \[\operatorname{Re}(z)=\frac{7}{2}\]

    C) \[\operatorname{Re}(z)\in \left\{ \frac{3}{2},\frac{7}{2} \right\}\]

    D) None of these

    Correct Answer: C

    Solution :

    \[|z\,-2|=\,\,min\,\left\{ \left| z-1 \right|<\left| z-5 \right| \right\}\] i.e., \[\left| z\,-2 \right| = \left| z-1 \right|,\,\,where\,\,\left| z\,-1 \right|<\left| z\,- 5 \right|\] \[\Rightarrow \,\,\,\operatorname{Re}(z) = \frac{3}{2}\,\,\,which  satisfy \left| z-5 \right|\,<\,\,\left| z-1 \right|\] Also, \[\left| z\,-2 \right|=\left| z\,-5 \right|, where\, \left| z\,-5 \right|<\left| z-1 \right|\] \[\Rightarrow \,\,\,\operatorname{Re}(z)= \frac{7}{2} \,which  satisfy\,\,\left| z\,-5 \right|\,\,\left| z\,-1 \right|\]


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