MCQ
$\tan \left( {2{{\cos }^{ - 1}}\frac{3}{5}} \right) = $
  • A
    $\frac{7}{{25}}$
  • B
    $\frac{{24}}{{25}}$
  • $ - \frac{{24}}{7}$
  • D
    $\frac{8}{3}$

Answer

Correct option: C.
$ - \frac{{24}}{7}$
c
(c) $\tan \left( {2{{\cos }^{ - 1}}\frac{3}{5}} \right) = \tan \left[ {{{\cos }^{ - 1}}\left( {2.\frac{9}{{25}} - 1} \right)} \right]$

{Since $2{\cos ^{ - 1}}x = {\cos ^{ - 1}}(2{x^2} - 1)$}

$ = \tan {\cos ^{ - 1}}\left( { - \frac{7}{{25}}} \right) = \tan {\tan ^{ - 1}}\left[ {\sqrt {\frac{{1 - \frac{{49}}{{625}}}}{{ - \frac{7}{{25}}}}} } \right] = - \frac{{24}}{7}$

Therefore $\tan \left( {2{{\cos }^{ - 1}}\frac{3}{5}} \right) = - \frac{{24}}{7}$.

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

The vector $2\,i + j - k$ is perpendicular to $i - 4j + \lambda k,$ if $\lambda = $
$\int\limits_0^{\frac{\pi }{4}} {} (tan^n x + tan^{n -2} x) d (x - [x])$ is : ( $[. ]$ denotes greatest integer function)
Let $f$ be a function satisfying $f(xy) = \frac{f(x)}{y}$ for all positive real numbers $x$ and $y.$ If $ f(30) = 20,$ then the value of $f(40)$ is-
For $\alpha, \beta, \gamma, \in R$, if $\lim _{x \rightarrow 0} \frac{x^2 \sin \alpha x +(\gamma-1) e ^{ x ^2}}{\sin 2 x -\beta x }=3$, then $\beta+\gamma-\alpha$ is equal to:
If $\mathop \sum \limits_{i = 1}^9 \left( {{x_i} - 5} \right) = 9$ and $\mathop \sum \limits_{i = 1}^9 {\left( {{x_i} - 5} \right)^2} = 45,$ then the standard deviation of the $9$ items  ${x_1},{x_2},\;.\;.\;.\;,{x_9}$ is :
The order of $[x\,y\,z]\,\,\left[ {\begin{array}{*{20}{c}}a&h&g\\h&b&f\\g&f&c\end{array}} \right]\,\left[ \begin{array}{l}x\\y\\z\end{array} \right]$ is
Let $f :\left[\frac{1}{2}, 1\right] \rightarrow R$ (the set of all real numbers) be a positive, non-constant and differentiable function such that $f^{\prime}(x)<2 f(x)$ and $f\left(\frac{1}{2}\right)=1$. Then the value of $\int_{1 / 2}^1 f(x) d x$ lies in the interval
The number of words, with or without meaning, that can be formed by taking $4$ letters at a time from the letters of the word $'SYLLABUS'$ such that two letters are distinct and two letters are alike, is
If $P(x_1, y_1)$ and $Q(x_2, y_2)$ are points on $2x + 3y + 1 = 0$ such that $|PA - PB|$ is maximum and $|QA - QB|$ is minimum, where $A(2,0)$ and $B(0,2)$, then value of $x_1 - y_1 + x_2 - y_2 $ is -
If $\theta$ denotes the acute angle between the curves, $y = 10 - x^2$ and $y = 2 + x^2$ at a point of their intersection, then $|\tan \,\theta |$ is equal to