MCQ
${\cot ^{ - 1}}\frac{3}{4} + {\sin ^{ - 1}}\frac{5}{{13}} = $
  • ${\sin ^{ - 1}}\frac{{63}}{{65}}$
  • B
    ${\sin ^{ - 1}}\frac{{12}}{{13}}$
  • C
    ${\sin ^{ - 1}}\frac{{65}}{{68}}$
  • D
    ${\sin ^{ - 1}}\frac{5}{{12}}$

Answer

Correct option: A.
${\sin ^{ - 1}}\frac{{63}}{{65}}$
a
(a) Let ${\cot ^{ - 1}}\frac{3}{4} = \theta \,\, \Rightarrow \,\,\cot \theta = \frac{3}{4}$

and $\sin \theta = \frac{1}{{\sqrt {1 + {{\cot }^2}\theta } }} = \frac{1}{{\sqrt {1 + (9/16)} }} = \frac{4}{5}$

Hence ${\cot ^{ - 1}}\frac{3}{4} + {\sin ^{ - 1}}\frac{5}{{13}} = {\sin ^{ - 1}}\frac{4}{5} + {\sin ^{ - 1}}\frac{5}{{13}}$

$ = {\sin ^{ - 1}}\left[ {\frac{4}{5}.\sqrt {1 - \frac{{25}}{{169}}} + \frac{5}{{13}}.\,\sqrt {1 - \frac{{16}}{{25}}} } \right]$

$ = {\sin ^{ - 1}}\left[ {\frac{4}{5}.\frac{{12}}{{13}} + \frac{5}{{13}}.\frac{3}{5}} \right]$

$ = {\sin ^{ - 1}}\left[ {\frac{{48 + 15}}{{65}}} \right] = {\sin ^{ - 1}}\frac{{63}}{{65}}$.

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 $y=y(x)$ be the solution of the differential equation $\frac{d y}{d x}=(y+1)\left((y+1) e^{x^{2} / 2}-x\right), y(2)=0$ then $y'(1)$  equal to . . .  .
Let $F: R \rightarrow R$ be a thrice differentiable function. Suppose that $F (1)=0, F (3)=-4$ and $F^{\prime}( x )<0$ for all $x \in$ $(1 / 2,3)$. Let $f(x)=x F(x)$ for all $x \in R$.

$1.$ The correct statement$(s)$ is(are)

$(A)$ $f^{\prime}(1) < 0$

$(B)$ $f(2) < 0$

$(C)$ $f^{\prime}(x) \neq 0$ for any $x \in(1,3)$

$(D)$ $f^{\prime}(x)=0$ for some $x \in(1,3)$

$2.$ If $\int_1^3 x^2 F^{\prime}(x) d x=-12$ and $\int_1^3 x^3 F^{\prime \prime}(x) d x=40$, then the correct expression$(s)$ is(are)

$(A)$ $9 f^{\prime}(3)+f^{\prime}(1)-32=0$

$(B)$ $\int_1^3 f(x) d x=12$

$(C)$ $9 f^{\prime}(3)-f^{\prime}(1)+32=0$

$(D)$ $\int_1^3 f(x) d x=-12$

Give the answer question $1$ and $2.$

Among all sectors of a fixed perimeter, choose the one with maximum area. Then, the angle at the centre of this sector (i.e., the angle between the bounding radii) is
Let $f\left( x \right) = \left\{ \begin{gathered}
  {\left( {x - 1} \right)^{\frac{1}{{2 - x}}}},\,\,\,x > 1,x \ne 2 \hfill \\
  k\,,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,x = 2 \hfill \\ 
\end{gathered}  \right.$ The value of $k$ for which $f$ is continuous at $x\, = 2$ is
To which of the following types the straight lines represented by $2x + 3y - 7 = 0$ and $2x + 3y - 5 = 0$ belong
The integral $\int_{1 / 4}^{3 / 4} \cos \left(2 \cot ^{-1} \sqrt{\frac{1-\mathrm{x}}{1+\mathrm{x}}}\right) \mathrm{dx}$ is equal to:
Let $A =\left\{\theta \in(0,2 \pi): \frac{1+2 i \sin \theta}{1- i \sin \theta}\right.$ is purely imaginary $\}$. Then the sum of the elements in $A$ is
If ${x^2} + 2x + 2xy + my - 3$ has two rational factors, then the value of $m$ will be
Let $y=y(x)$ be the solution of the differential equation   $\sec ^2 x d x+\left(e^{2 y} \tan ^2 x+\tan x\right) d y=0 $  , $0 < x < \frac{\pi}{2}, y\left(\frac{\pi}{4}\right)=0$. If $y\left(\frac{\pi}{6}\right)=\alpha$,  Then $\mathrm{e}^{8 \alpha}$ is equal to............
If direction cosines of two lines are proportional to $(2, 3, -6)$ and $(3, -4, 5)$, then the acute angle between them is