MCQ
A primitive of $f(x) = \frac{x}{{1 + {x^2}}}$  $dx$=
  • A
    ${\log _e}({x^2} + 1)$
  • B
    $x{\tan ^{ - 1}}x$
  • $\frac{{{{\log }_e}({x^2} + 1)}}{2}$
  • D
    $\frac{1}{2}x{\tan ^{ - 1}}x$

Answer

Correct option: C.
$\frac{{{{\log }_e}({x^2} + 1)}}{2}$
c
(c)$f(x) = \frac{x}{{1 + {x^2}}}$, $\therefore \,\,\,I = \int_{}^{} {f(x)} = \int_{}^{} {\frac{x}{{1 + {x^2}}}\,dx} $
Put $1 + {x^2} = t$

$\Rightarrow 2x\,dx = dt \Rightarrow x\,dx = dt2$
$\therefore \,\,\,I = \frac{1}{2}\int_{}^{} {\frac{{dt}}{t} = \frac{1}{2}\log t + c} $; $I = \frac{1}{2}\log (1 + {x^2}) + c$.

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

Statement $-1$ : Any function $f (x)$ is even function, when $f (-x) = f (x)$ over its specified domain. 

Statement $-2$ : $f(x) = \frac{1}{{\sqrt {1 - {x^2}} }} + \left[ {\frac{{{x^2} + x + 1}}{4}} \right]$ , where $[.]$ is greatest integer function. Function $f(x)$ is even function

Match the statements/expressions given in Column $I$ with the values given in Column $II$.

Column $I$ Column $II$

$(A)$ Root$(s)$ of the equation

$2 \sin ^2 \theta+\sin ^2 2 \theta=2$

$(p)$ $\frac{\pi}{6}$

$(B)$ Points of discontinuity of the function

$f(x)=\left[\frac{6 x}{\pi}\right] \cos \left[\frac{3 x}{\pi}\right],$

where $[y]$ denotes the largest integer less than or equal to $y$

$(q)$ $\frac{\pi}{4}$

$(C)$ Volume of the parallelopiped with its edges represented by the vectors

$\hat{i}+\hat{j}, \quad \hat{i}+2 \hat{j} \text { and } \hat{i}+\hat{j}+\pi \hat{k}$

$(r)$ $\frac{\pi}{3}$

$(D)$ Angle between vectors $\vec{a}$ and $\vec{b}$ where $\vec{a}, \vec{b}$ and $\vec{c}$ are unit vectors satisfying

$\vec{a}+\vec{b}+\sqrt{3} \vec{c}=\overrightarrow{0}$

$(s)$ $\frac{\pi}{2}$
  $(t)$ $\pi$
The area of the region bounded by $y = | x – 1 |$ and $y = 1$ is:
The value of $ \cos^{-1}\left (\cot \left (\dfrac {\pi}{2}\right )\right ) + \cos^{-1} \left (\sin \left (\dfrac {2\pi}{3}\right )\right )$ is:
For the differentiable function $f: R -\{0\} \rightarrow R$, let $3 f(x)+2 f\left(\frac{1}{x}\right)=\frac{1}{x}-10$, then $\left|f(3)+f^{\prime}\left(\frac{1}{4}\right)\right|$ is equal to
A vector parallel to the line of intersection of the plance $\vec{\text{r}}.(3\hat{\text{i}}-\hat{\text{j}}+\hat{\text{k}})=1$ and $\vec{\text{r}}.(\hat{\text{i}}-4\hat{\text{j}}+2\hat{\text{k}})=2$ is:
Let $A$ and $B$ be two events such that $P(A) = 0.6, P(B) = 0.2, P(A|B) = 0.5.$ Then $\text{P}(\overline{\text{A}}|\overline{\text{B}})$ equals.
One vertex of a rectangular parallelopiped is at the origin $O$ and the lengths of its edges along $x , y$ and $Z$ axes are $3,4$ and $5$ units respectively. Let $P$ be the vertex $(3,4,5)$. Then the shortest distance between the diagonal $OP$ and an edge parallel to $Z$ axis, not passing through $O$ or $P$ is:
The magnitude of the projection of the vector $2\hat i + 3\hat j + \hat k$ on the vector perpendicular to the plane containing the vectors $\hat i + \hat j + \hat k$ and $\hat i + 2\hat j + 3\hat k$ is
$\int_{}^{} {\frac{{\log x\;dx}}{{{x^3}}} = } $