CEE Kerala Engineering CEE Kerala Engineering Solved Paper-2010

  • question_answer
    The angle between the curves,\[y={{x}^{2}}\]and \[{{y}^{2}}-x=0\]at the point (1, 1), is

    A)  \[\frac{\pi }{2}\]                                             

    B)  \[{{\tan }^{-1}}\frac{4}{3}\]

    C)  \[\frac{\pi }{3}\]                             

    D)         \[\frac{\pi }{4}\]

    E)  \[{{\tan }^{-1}}\frac{3}{4}\]

    Correct Answer: E

    Solution :

    Given curve are \[y={{x}^{2}}\]                                    ...(i) and        \[{{y}^{2}}-x=0\]                                  ...(ii) From Eq. (i),                 \[\frac{dy}{dx}=2x\] \[\therefore \]  \[{{\left( \frac{dy}{dx} \right)}_{(1,1)}}=2={{m}_{1}}\]    (say) From Eq. (ii),                 \[2y\frac{dy}{dx}-1=0\] \[\Rightarrow \]               \[\frac{dy}{dx}=\frac{1}{2y}\] \[\therefore \]  \[{{\left( \frac{dy}{dx} \right)}_{(1,1)}}=\frac{1}{2}={{m}_{2}}\]              (say) Let\[\theta \]be the angle between given curve. Then,                 \[\tan \theta =\frac{{{m}_{1}}-{{m}_{2}}}{1+{{m}_{1}}{{m}_{2}}}\]                 \[=\frac{2-\frac{1}{2}}{1+2.\frac{1}{2}}=\frac{3/2}{2}=\frac{3}{4}\] \[\therefore \]  \[\theta ={{\tan }^{-1}}\frac{3}{4}\]


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