MCQ
${d \over {dx}}\left\{ {{{\cos }^{ - 1}}\left( {{{1 - {x^2}} \over {1 + {x^2}}}} \right)} \right\} = $
  • A
    ${1 \over {1 + {x^2}}}$
  • B
    $ - {1 \over {1 + {x^2}}}$
  • C
    $ - {2 \over {1 + {x^2}}}$
  • ${2 \over {1 + {x^2}}}$

Answer

Correct option: D.
${2 \over {1 + {x^2}}}$
d
(d) $\frac{d}{{dx}}\left\{ {{{\cos }^{ - 1}}\left( {\frac{{1 - {x^2}}}{{1 + {x^2}}}} \right)} \right\}$

Let $\frac{{1 - {x^2}}}{{1 + {x^2}}} = \cos \theta $

==> $1 - {x^2} = (1 + {x^2})\cos \theta $

==> $ - {x^2}(1 + \cos \theta ) = \cos \theta - 1$

==> ${x^2} = \frac{{1 - \cos \theta }}{{1 + \cos \theta }} = \frac{{2{{\sin }^2}\frac{\theta }{2}}}{{2{{\cos }^2}\frac{\theta }{2}}} = {\tan ^2}\frac{\theta }{2}$

or $x = \tan \frac{\theta }{2}$ or $\theta = 2{\tan ^{ - 1}}x$

So, $\frac{d}{{dx}}[\theta ] = \frac{d}{{dx}}[2{\tan ^{ - 1}}x] = \frac{2}{{1 + {x^2}}}$.

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

If ${z_1},{z_2}$ and ${z_3},{z_4}$ are two pairs of conjugate complex numbers, then $arg\left( {\frac{{{z_1}}}{{{z_4}}}} \right) + arg\left( {\frac{{{z_2}}}{{{z_3}}}} \right)$ equals
$\tan 3A - \tan 2A - \tan A = $
The number of integers $a$ in the interval $[1,2014]$ for which the system of equations $x+y=a$, $\frac{x^2}{x-1}+\frac{y^2}{y-1}=4$ has finitely many solutions is
Let $S$ be the set of all $a \in N$ such that the area of the triangle formed by the tangent at the point $P ( b , c ), b , c \in N$, on the parabola $y ^2=2 ax$ and the lines $x=b, y=0$ is $16$ unit $^2$, then $\sum_{\text {aes }} a$ is equal to $..........$.
If $\left\{a_{i}\right\}_{i=1}^{n}$ where $n$ is an even integer, is an arithmetic progression with common difference $1$ , and $\sum \limits_{ i =1}^{ n } a _{ i }=192, \sum \limits_{ i =1}^{ n / 2} a _{2 i }=120$, then $n$ is equal to
Let $O$ be the origin and let $P Q R$ be an arbitrary triangle. The point $S$ is such that

$\overline{O P} \cdot \overline{O Q}+\overline{O R} \cdot \overline{O S}=\overline{O R} \cdot \overline{O P}+\overline{O Q} \cdot \overline{O S}=\overline{O Q} \cdot \overline{O R}+\overline{O P} \cdot \overline{O S}$

Then the triangle $P Q R$ has $S$ as its

The condition that the line $x\cos \alpha + y\sin \alpha = p$ may touch the circle ${x^2} + {y^2} = {a^2}$ is
Let there be three independent events $E _{1}, E _{2}$ and $E _{3}$. The probability that only $E _{1}$ occurs is $\alpha$, only $E _{2}$ occurs is $\beta$ and only $E _{3}$ occurs is $\gamma .$ Let $'p'$ denote the probability of none of events occurs that satisfies the equations $(\alpha-2 \beta) p =\alpha \beta$ and $(\beta-3 \gamma) p =2 \beta \gamma .$ All the given probabilities are assumed to lie in the interval $(0,1)$

Then, $\frac{\text { Probability of occurrence of } E _{1}}{\text { Probability of occurrence of } E _{3}}$ is equal to ..........

The equation $2{x^2} + 3{y^2} = 30$ represents
Let $a, b \in R$. Let the mean and the variance of $6$ observations $-3,4,7,-6$, $a,\ b$ be $2$ and $23$ , respectively. The mean deviation about the mean of these $6$ observations is :