JEE Main & Advanced Mathematics Functions Question Bank Self Evaluation Test - Relation and Functions-II

  • question_answer
    Let \[f:R\to R\] be a function defined by \[f(x)=\frac{x-m}{x-n},\] where \[m\ne n,\] then

    A) f is one-one onto

    B) f is one-one into

    C) f is many-one onto

    D) f is many-one into

    Correct Answer: B

    Solution :

    [b] Let \[f:R\to R\] be a function defined by \[f(x)=\frac{x-m}{x-n}\] For any \[(x,y)\in R\] Let \[f(x)=f(y)\] \[\Rightarrow \frac{x-m}{x-n}=\frac{y-m}{y-n}\Rightarrow x=y\therefore \] f is one-one Let \[\alpha \in R\] such that \[f(x)=\alpha \] \[\Rightarrow a=\frac{x-m}{x-n}\Rightarrow (x-n)\alpha =x-m\] \[\Rightarrow x=\frac{n\alpha -m}{\alpha -1}.\] for \[\alpha =1,x\notin R\] so, f is not onto.


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