CEE Kerala Engineering CEE Kerala Engineering Solved Paper-2007

  • question_answer
    \[y=2{{e}^{2x}}-{{e}^{-x}}\]is a solution of the differential equation

    A)  \[{{y}_{2}}+{{y}_{1}}+2y=0\]

    B)  \[{{y}_{2}}-{{y}_{1}}+2y=0\]

    C)  \[{{y}_{2}}+{{y}_{1}}=0\]

    D)  \[{{y}_{2}}-{{y}_{1}}-2y=0\]

    E)  \[{{y}_{2}}-2{{y}_{1}}-y=0\]

    Correct Answer: D

    Solution :

    Given that, \[y=2{{e}^{2x}}-{{e}^{-x}}\] On differentiating w.r.t.\[x,\]we get \[{{y}_{1}}=4{{e}^{2x}}+{{e}^{-x}}\] Now, on again differentiating w.r.t.\[x,\]we get                 \[{{y}_{2}}=8{{e}^{2x}}-{{e}^{-x}}\] Now,     \[{{y}_{2}}-{{y}_{1}}-2y\]                 \[=8{{e}^{2x}}-{{e}^{-x}}-4{{e}^{2x}}-{{e}^{-x}}-4{{e}^{2x}}+2{{e}^{-x}}\]                 \[=0\]


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