MCQ
The function ${1 \over {1 + {x^2}}}$ is decreasing in the interval
  • A
    $( - \infty ,\, - 1]$
  • B
    $( - \infty ,\,0]$
  • C
    $[1,\infty )$
  • $(0,\infty )$

Answer

Correct option: D.
$(0,\infty )$
d
(d) $y = \frac{1}{{1 + {x^2}}}$==>$\frac{{dy}}{{dx}} = - \frac{{2x}}{{{{(1 + {x^2})}^2}}}$

To be decreasing, $ - \frac{{2x}}{{{{(1 + {x^2})}^2}}} < 0$

==>$x > 0 \Rightarrow x \in (0,\infty )$.

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 $A$ be a matrix of order $2 \times 2$, whose entries are from the set $\{0,1,2,3,4,5\}$. If the sum of all the entries of $A$ is a prime number $p , 2< p <8$, then the number of such matrices $A$ is
Which of the following equations in parametric form can represent a hyperbola, where $'t'$  is a parameter.
The function $y = a(1 - \cos x)$ is maximum when $x = $
Let $\overrightarrow{ a }=2 \hat{ i }+\hat{ j }+\hat{ k }$, and $\overrightarrow{ b }$ and $\overrightarrow{ c }$ be two nonzero vectors such that $|\vec{a}+\vec{b}+\vec{c}|=|\vec{a}+\vec{b}-\vec{c}| \quad$ and $\vec{b} \cdot \vec{c}=0$. Consider the following two statement:

$(A)$ $|\overrightarrow{ a }+\lambda \overrightarrow{ c }| \geq|\overrightarrow{ a }|$ for all $\lambda \in R$.

$(B)$ $\overrightarrow{ a }$ and $\overrightarrow{ c }$ are always parallel

If ${I_1} = \int\limits_0^1 {{e^{ - x}}} {\cos ^2}\,x\,dx\,;\,{I_2} = \int\limits_0^1 {{e^{ - {x^2}}}} {\cos ^2}\,x\,dx$ and $\,{I_3} = \int\limits_0^1 {{e^{ - {x^3}}}} dx$ ; then
If $y=y(x)$ and it follows the relation $4x{e^{xy}} = y + 5{\sin ^2}x$ ,then $y'(0)$ is equal to
The domain of the function

$f(x)=\sin ^{-1}\left(\frac{3 x^{2}+x-1}{(x-1)^{2}}\right)+\cos ^{-1}\left(\frac{x-1}{x+1}\right)$ is :

The equation ${4^{({x^2} + 2)}} - {9.2^{({x^2} + 2)}} + 8 = 0$ has the solution
If the variable line $y = kx + 2h$ is tangent to an ellipse $2x^2 + 3y^2 = 6$ , the locus of $P (h, k)$ is a conic $C$ whose eccentricity equals
The number of different possible values for the sum $x+y+z$, where $x, y, z$ are real number such that $x^4+4 y^4+16 z^4+64=32 x y z$ is