MCQ
The function $f(x)=\cot ^{-1} x+x$ increases in the interval
  • A
    $(1, \infty)$
  • B
    $(-1, \infty)$
  • C
    $(0, \infty)$
  • $(-\infty, \infty)$

Answer

Correct option: D.
$(-\infty, \infty)$
(d) : $f(x)=\cot ^{-1} x+x$
$
\Rightarrow f^{\prime}(x)=\frac{-1}{1+x^2}+1 \Rightarrow f^{\prime}(x)=\frac{x^2}{1+x^2} \geq 0 \text {, for } x \in R
$
$\therefore f(x)$ is increasing on $(-\infty, \infty)$.

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 $f(x) = \,\left\{ {\begin{array}{*{20}{c}}   {\frac{{\sin \pi x}}{{5x}},}&{x \ne 0} \\    {k,}&{x = 0}  \end{array}} \right.$ if $f(x)$  is continuous at  $x = 0,$  then $k=$
$\mathop {\lim }\limits_{n \to \infty } \frac{{1 + {2^4} + {3^4} + .... + {n^4}}}{{{n^5}}}$$ - \mathop {\lim }\limits_{n \to \infty } \frac{{1 + {2^3} + {3^3} + .... + {n^3}}}{{{n^5}}} = $
Let the co-ordinates of one vertex of $\triangle ABC$ be $A (0,2, \alpha)$ and the other two vertices lie on the line $\frac{x+\alpha}{5}=\frac{y-1}{2}=\frac{z+4}{3}$. For $\alpha \in Z$, if the area of $\triangle ABC$ is $21$ sq. units and the line segment $BC$ has length $2 \sqrt{21}$ units, then $\alpha^2$ is equal to $...........$.
The vectors $\overrightarrow {AB} = 3i + 4k,$ and $\overrightarrow {AC} = 5i - 2j + 4k$ are the sides of a triangle $ABC$ . The length of the median through $A $ is
$\int_{}^{} {{e^x}\sin x(\sin x + 2\cos x)} \;dx = $
If $A$ and $B$ are two events such that $\text{A}\neq\phi,\text{B}=\phi,$ then,
Consider the line $\mathrm{L}$ passing through the points $(1,2,3)$ and $(2,3,5)$. The distance of the point $\left(\frac{11}{3}, \frac{11}{3}, \frac{19}{3}\right)$ from the line $\mathrm{L}$ along the line $\frac{3 x-11}{2}=\frac{3 y-11}{1}=\frac{3 z-19}{2}$ is equal to :
The direction cosines of any normal to the $xy$ plane are:
The function $f(x) = 2{x^3} - 3{x^2} - 12x + 4$ has
Fifteen football players of a club-team are given $15$ T-shirts with their names written on the backside. If the players pick up the T-shirts randomly, then the probability that at least $3$ players pick the correct $T$-shirt is