JEE Main & Advanced Mathematics Differentiation Question Bank Differentiation of implicit function Parametric

  • question_answer
    If \[x=a{{t}^{2}},y=2at\], then \[\frac{{{d}^{2}}y}{d{{x}^{2}}}=\]                   [Karnataka CET 1993]

    A)            \[-\frac{1}{{{t}^{2}}}\]

    B)            \[\frac{1}{2a{{t}^{3}}}\]

    C)            \[-\frac{1}{{{t}^{3}}}\]

    D)            \[-\frac{1}{2a{{t}^{3}}}\]

    Correct Answer: D

    Solution :

               \[\frac{dy}{dx}=\frac{dy/dt}{dx/dt}=\frac{2a}{2at}\] Þ \[\frac{dy}{dx}=\frac{1}{t}=\frac{2a}{y}\]                    Þ  \[y\frac{dy}{dx}=2a\]Þ \[y\frac{{{d}^{2}}y}{d{{x}^{2}}}+{{\left( \frac{dy}{dx} \right)}^{2}}=0\]                    \[\Rightarrow \frac{{{d}^{2}}y}{d{{x}^{2}}}=\frac{-{{(dy/dx)}^{2}}}{y}=-\frac{1}{2a{{t}^{3}}}\].


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