JEE Main & Advanced Sample Paper JEE Main - Mock Test - 37

  • question_answer
    Equation of the tangent to the curve \[y={{e}^{-|x|}}\] at the point where it cuts the line x = 1 -

    A) Is \[ey+x=2\]     

    B) Is \[x+y=e\]

    C) Is \[ex+y=1\]     

    D)        Does not exist

    Correct Answer: A

    Solution :

    [a] The point of intersection is \[\left( 1,\text{ }{{e}^{-1}} \right)\] \[\because \,x=1\], so equation of the curve is \[y={{e}^{-x}}\] \[\Rightarrow \frac{dy}{dx}=-{{e}^{-x}}\] \[{{\left[ \frac{dy}{dx} \right]}_{x=1}}=-{{e}^{-1}}\]. Hence equation of tangent is \[y-{{e}^{-1}}=-{{e}^{-1}}\left( x-1 \right)\text{ }or,\text{ }ey+x=2.\] 


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