J & K CET Engineering J and K - CET Engineering Solved Paper-2012

  • question_answer
    The degree of the differential equation satisfied by the curve \[\sqrt{1+x}-a\,\sqrt{1+y}=1,\] where a is a parameter, is

    A)  \[1\]                 

    B)  \[2\]

    C)  \[3\]               

    D)  None of these

    Correct Answer: A

    Solution :

    Given equation is \[\sqrt{1+x}-a\sqrt{1+y}=1\] ?.(i) On differentiating w. r. t. x, we get \[\frac{1}{2\sqrt{1+x}}-\frac{a}{2+\sqrt{1+y}}.\frac{dy}{dx}=0\] \[\Rightarrow \] \[a=\frac{\sqrt{1+y}}{\sqrt{1+x}}.\frac{dx}{dy}\] On putting the value of a in Eq. (i), we get \[\sqrt{1+x}-\frac{\sqrt{1+y}}{\sqrt{1+x}}.\frac{dx}{dy}\times \sqrt{1+y}=1\] \[\Rightarrow \] \[(1+x)-(1+y).\frac{dx}{dy}=\sqrt{1+x}\] Hence, the degree is 1.


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