Manipal Engineering Manipal Engineering Solved Paper-2009

  • question_answer
    \[\underset{x\to \infty }{\mathop{\lim }}\,{{\left( \frac{x+5}{x+2} \right)}^{x+3}}\]equals

    A) \[e\]                                     

    B) \[{{e}^{2}}\]

    C) \[{{e}^{3}}\]                      

    D)        \[{{e}^{5}}\]

    Correct Answer: C

    Solution :

    \[\underset{x\to \infty }{\mathop{\lim }}\,{{\left( \frac{x+5}{x+2} \right)}^{x+3}}=\underset{x\to \infty }{\mathop{\lim }}\,{{\left( 1+\frac{3}{x+2} \right)}^{x+3}}\]                                 \[=\underset{x\to \infty }{\mathop{\lim }}\,{{\left[ {{\left( 1+\frac{3}{x+2} \right)}^{\frac{x+2}{3}}} \right]}^{\frac{3(x+3)}{x+2}}}\]                                 \[={{e}^{\underset{x\to \infty }{\mathop{\lim }}\,3\left( \frac{1+\frac{3}{x}}{1+\frac{2}{x}} \right)}}={{e}^{3}}\]


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