MCQ
$\mathop {\lim }\limits_{x \to {0^ + }} \left\{ {{{\left( {1 + x} \right)}^{\frac{2}{x}}}} \right\}$ is equal to (where $\{.\}$ denotes the fractional part of $x$)
  • $e^2 -7$
  • B
    $e^2 -8$
  • C
    $e^2 -6$
  • D
    $7$

Answer

Correct option: A.
$e^2 -7$
a
As $\left\{(1+x)^{\frac{2}{x}}\right\}=(1+x)^{\frac{2}{x}}-\left[(1+x)^{\frac{2}{x}}\right]$

And $\lim _{x \rightarrow 0}(1+x)^{\frac{2}{x}}=\exp \lim _{x \rightarrow 0}\left(\frac{2}{x} \log (1+x)\right)=\exp \lim _{x \rightarrow 0}\left(\frac{2 \frac{1}{1+x}}{1}\right)=e^{2}$

since$\left[\lim _{x \rightarrow \infty} f(x)^{g(x)}=e^{\left(\lim _{x \rightarrow \infty} g(x) \cdot \ln f(x)\right)}\right]$

$\therefore \lim _{x \rightarrow 0}\left\{(1+x)^{\frac{2}{x}}\right\}=e^{2}-\left[e^{2}\right]=e^{2}-7$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free