MCQ
$\int_{}^{} {\frac{{dx}}{{1 + 3{{\sin }^2}x}} = } $
  • A
    $\frac{1}{3}{\tan ^{ - 1}}(3{\tan ^2}x) + c$
  • $\frac{1}{2}{\tan ^{ - 1}}(2\tan x) + c$
  • C
    ${\tan ^{ - 1}}(\tan x) + c$
  • D
    None of these

Answer

Correct option: B.
$\frac{1}{2}{\tan ^{ - 1}}(2\tan x) + c$
b
(b)$\int_{}^{} {\frac{{dx}}{{1 + 3{{\sin }^2}x}}} = \int_{}^{} {\frac{{dx}}{{{{\sin }^2}x + {{\cos }^2}x + 3{{\sin }^2}x}}} $
$ = \int_{}^{} {\frac{{dx}}{{4{{\sin }^2}x + {{\cos }^2}x}}} = \int_{}^{} {\frac{{{{\sec }^2}x\,dx}}{{4{{\tan }^2}x + 1}} = \frac{1}{4}\int_{}^{} {\frac{{{{\sec }^2}x\,dx}}{{{{\tan }^2}x + \frac{1}{4}}}} } $
Put $t = \tan x \Rightarrow dt = {\sec ^2}x\,dx,$ then it reduces to
$\frac{1}{4}\int_{}^{} {\frac{{dt}}{{{t^2} + {{\left( {\frac{1}{2}} \right)}^2}}}} = \frac{1}{4}2{\tan ^{ - 1}}(2t) + c$
$ = \frac{1}{2}{\tan ^{ - 1}}(2t) + c = \frac{1}{2}{\tan ^{ - 1}}(2\tan x) + 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

Are the points (1, 1), (2, 3) and (8, 11) collinear?
  1. collinear
  2. Non collinear
  3. coplaner
  4. None of above
If  $\begin{gathered} f(x)\, = \,\left\{ \begin{gathered}
  x\left( {\frac{{{e^{1/x}} - {e^{ - 1/x}}}}{{{e^{1/x}} + {e^{ - 1/x}}}}} \right)\,,\,\,x \ne 0 \hfill \\
  \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,0\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,,\,\,\,\,x\, = \,0\,\,\,\,\,\,\,\,\,\,\,\,\, \hfill \\ 
\end{gathered}  \right. \hfill \\
  \,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\ \hfill \\ 
\end{gathered}$ then correct statement is
If a function $g(x)$ is defined in $[-1, 1]$ and two vertices of an equilateral triangle are $(0, 0)$ and $(x, g(x))$ and its area is $\frac{\sqrt 3}{4}$ , then $g(x)$ equals :-
If ${\tan ^{ - 1}}x + {\cos ^{ - 1}}\frac{y}{{\sqrt {(1 + {y^2})} }} = {\sin ^{ - 1}}\frac{3}{{\sqrt {10} }}$ and both $x$ and $y$ are positive and integral, then $x$ and $y =$
Integrating factor of the differential equation, $(1-\text{x}^2)\frac{\text{dy}}{\text{dx}}-\text{xy}=1$ is:
  1. $-\text{x}$
  2. $\frac{\text{x}}{1+\text{x}^2}$
  3. $\sqrt{1-\text{x}^2}$
  4. $\frac{1}{2}\log(1-\text{x}^2)$
A curve is given by the equations $x = a\cos \theta + {1 \over 2}b\cos 2\theta ,$ $y = a\sin \theta + {1 \over 2}b\,\sin \,2\theta $, then the points for which ${{{d^2}y} \over {d{x^2}}} = 0,$ is given by
The region represented by the inequation system x, y ≥ 0, y ≤ 6, x + y ≤ 3 is:
  1. unbounded in first quadrant
  2. unbounded in first and second quadrants
  3. bounded in first quadrant
  4. none of these
The matrix $\left[ {\begin{array}{*{20}{c}}2&\lambda &{ - 4}\\{ - 1}&3&4\\1&{ - 2}&{ - 3}\end{array}} \right]$is non singular, if
Which of the following set of points are non- collinear
In a box containing $100$ bulbs, $10$ are defective. The probability that out of a sample of $5$ bulbs, none is defective is