MCQ
If $y=\left(1+\frac{1}{x}\right)^x$, then $\frac{d y}{d x}=$
  • A
    $\left(1+\frac{1}{x}\right)^x \log \left(1+\frac{1}{x}\right)$
  • B
    $\left(x+\frac{1}{x}\right)^x\left\{\log \left(1+\frac{1}{x}\right)+\frac{1}{x+1}\right\}$
  • $\left(1+\frac{1}{x}\right)^x\left\{\log \left(1+\frac{1}{x}\right)-\frac{1}{x+1}\right\}$
  • D
    $\left(x+\frac{1}{x}\right)^x\left\{\log (x+1)-\frac{x}{x+1}\right\}$

Answer

Correct option: C.
$\left(1+\frac{1}{x}\right)^x\left\{\log \left(1+\frac{1}{x}\right)-\frac{1}{x+1}\right\}$
$y=\left(1+\frac{1}{x}\right)^x$
Taking log on both sides,
$\log y=\log \left(1+\frac{1}{x}\right)^z$
$\log y=x \log \left(1+\frac{1}{x}\right)$
Differentiate with respect to $x,$
$\frac{1}{y} \frac{d y}{d x}=x \times \frac{1}{1+\frac{1}{x}} \times \frac{-1}{x^2}+\log \left(1+\frac{1}{x}\right)$
$\frac{1}{y} \frac{d y}{d x}=\frac{x^2}{x+1} \times \frac{-1}{x^2}+\log \left(1+\frac{1}{x}\right)$
$\frac{d y}{d x}=y\left(\frac{-1}{x+1}+\log \left(1+\frac{1}{x}\right)\right)$
$\frac{d y}{d x}=\left(1+\frac{1}{x}\right)^x\left(\frac{-1}{x-1}+\log \left(1+\frac{1}{x}\right)\right)$
$\frac{d y}{d x}=\left(1+\frac{1}{x}\right)^x\left(\log \left(1+\frac{1}{x}\right)-\frac{1}{x+1}\right)$

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

Similar questions

Let ${I_1} = \int\limits_0^1 {\frac{{{e^x}}}{{\left( {1 + x} \right)}}} \,dx$ and ${I_2} = \int\limits_0^1 {\frac{{{x^2}}}{{{e^{{x^3}}}\left( {2 - {x^3}} \right)}}} \,dx$ then value of $\frac{{{I_1}}}{{{I_2}}}$ is equal to
If $f(x) = \cos x\cos 2x\cos 4x\cos 8x\cos 16x$, then $f'\left( {{\pi \over 4}} \right)$ is
In an LPP, if the objective function $z=a x+$ by has the same maximum value on two corner points of the feasible region, then the number of points at which $z_{\max }$ occurs is
Find the area of the triangle with vertices $P(4,5), Q(4,-2)$ and $R(-6,2)$.
Choose the correct answer from the given four options.The general solution of $\frac{\text{dy}}{\text{dx}}=2\text{x}\ \text{e}^{\text{x}^{2}-\text{y}}$ is:
The equation of the normal to the curve $x = a \cos^3 \theta , y = a \sin^3 \theta$ at the point $\theta=\frac{\pi}{4}$ is :
If two or more vectors are parallel to the same line, irrespective of their magnitudes and directions, then they are:
$\lim\limits_{\text{n}\rightarrow\infty}\Big\{\frac{1}{2\text{n}+1}+\frac{1}{2\text{n}+2}+\ .....+\frac{1}{2\text{n}+\text{n}}\Big\}$ is equal to:
For a non - zero, real $a, b$ and $c$ $\left| {\begin{array}{*{20}{c}}{\frac{{{a^2} + {b^2}}}{c}}&c&c\\a&{\frac{{{b^2} + {c^2}}}{a}}&a\\b&b&{\frac{{{c^2} + {a^2}}}{b}} \end{array}} \right|$ $= \alpha \, abc$, then the values of $\alpha$ is
The value of $x$  obtained from the equation $\left| {\,\begin{array}{*{20}{c}}{x + \alpha }&\beta &\gamma \\\gamma &{x + \beta }&\alpha \\\alpha &\beta &{x + \gamma }\end{array}\,} \right| = 0$ will be