JEE Main & Advanced Sample Paper JEE Main Sample Paper-32

  • question_answer
    Suppose that co and z are complex numbers such that both (1 + 2i) \[\omega \] and (1 + 2i)z are different real numbers. The slope of the line connecting \[\omega \] and z in the complex plane is

    A) \[-2\]         

    B)       \[-1/2\]

    C) 2

    D) cannot be determined

    Correct Answer: A

    Solution :

    Let \[\omega ={{x}_{1}}+i{{y}_{1}}\] and \[z={{x}_{2}}+i{{y}_{2}}\] Now \[(1+2i)({{x}_{1}}+i{{y}_{1}})\,\] is real \[\Rightarrow \,2{{x}_{1}}+{{y}_{1}}=0\] \[\Rightarrow \,2{{x}_{2}}+{{y}_{2}}=0\] \[\therefore \,\,2{{x}_{1}}+{{y}_{1}}=2{{x}_{2}}+{{y}_{2}}\] \[\Rightarrow \,-2({{x}_{2}}-{{x}_{1}})={{y}_{2}}-{{y}_{1}}\]  \[\Rightarrow \,\frac{{{y}_{2}}-{{y}_{1}}}{{{x}_{2}}-{{x}_{1}}}=-2\]


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