JEE Main & Advanced Mathematics Functions Question Bank Self Evaluation Test - Relations and Functions-I

  • question_answer
    The domain for which the functions \[f(x)=2{{x}^{2}}-1\] and \[g(x)=1-3x\] is equal, i.e., \[f(x)=g(x).\], is

    A) \[\{0,\,\,2\}\]

    B)        \[\left\{ \frac{1}{2},-2 \right\}\]

    C) \[\left\{ -\frac{1}{2},2 \right\}\]

    D)        \[\left\{ \frac{1}{2},2 \right\}\]

    Correct Answer: B

    Solution :

    [b] For \[f(x)=g(x)\Rightarrow 2{{x}^{2}}-1=1-3x\] \[\Rightarrow 2{{x}^{2}}+3x-2=0\Rightarrow 2{{x}^{2}}+4x-x-2=0\] \[\Rightarrow 2x(x+2)-1(x+2)=0\Rightarrow (x+2)(2x-1)=0\] \[\Rightarrow \,\,\,x=-2,\,\,\frac{1}{2}\] \[\therefore \] The domain for which the function \[f(x)=g(x)\] is \[\left\{ -2,\,\,\,\frac{1}{2} \right\}.\]


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