JCECE Engineering JCECE Engineering Solved Paper-2010

  • question_answer
    The domain of the function\[f(x)=\sqrt{3-x}+{{\cos }^{-1}}\left( \frac{3-2x}{5} \right)\], is

    A) \[[-1,\,\,3]\]                      

    B) \[(-1,\,\,3]\]

    C) \[[-1,\,\,3)\]                      

    D)  None of these

    Correct Answer: A

    Solution :

    We have, the function                 \[f(x)=\sqrt{3-x}+{{\cos }^{-1}}\left( \frac{3-2x}{5} \right)\] For it's existence,                 \[3-x\ge 0\Rightarrow x\le 3\]                   ... (i) and        \[-1\le \frac{3-2x}{5}\le 1\] \[\Rightarrow \]               \[-5\le 3-2x\le 5\] \[\Rightarrow \]               \[-8\le -2x\le 2\] \[\Rightarrow \]               \[-1\le x\le 4\]                                   ... (ii) From Eqs. (i) and (ii), it is clear that the domain of the given function \[f\] is                 \[(-\infty ,\,\,3]\cap [-1,\,\,-4]=[-1,\,\,3]\]


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