MCQ
$I=\int \limits_{\pi / 4}^{\pi / 3}\left(\frac{8 \sin x-\sin 2 x}{x}\right) d x$. Then
  • A
    $\frac{\pi}{2} < I < \frac{3 \pi}{4}$
  • B
    $\frac{\pi}{5} < I < \frac{5 \pi}{12}$
  • $\frac{5 \pi}{12} < I < \frac{\sqrt{2}}{3} \pi$
  • D
    $\frac{3 \pi}{4} < I < \pi$

Answer

Correct option: C.
$\frac{5 \pi}{12} < I < \frac{\sqrt{2}}{3} \pi$
c
Consider

$f(x)=8 \sin x-\sin 2 x$

$f^{\prime}(x)=8 \sin x-2 \cos 2 x$

$f^{\prime \prime}(x)=-8 \sin x+4 \sin 2 x$

$=-8 \sin x(1-\cos x)$

$\therefore f^{\prime \prime}(x)<0 x \in\left(\frac{\pi}{4}, \frac{\pi}{3}\right)$

$\therefore f ^{\prime}( x )$ is $\downarrow$ function

$f^{\prime}\left(\frac{\pi}{3}\right)$

$5 < f^{\prime}(x)<\frac{8}{\sqrt{2}}$

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

The points $D, E, F $ divide $ BC, CA $ and $AB $ of the triangle $ABC$ in the ratio $1 : 4, 3 : 2 $ and $3 : 7 $ respectively and the point $ K$  divides $ AB$  in the ratio $1:3$, then $(\overrightarrow {AD} + \overrightarrow {BE} + \overrightarrow {CF} )\,\,:\,\,\overrightarrow {CK} $ is equal to
Let A = {2, 3, 4, 5, ..., 17, 18}. Let $'\simeq'$ be the equivalence relation on A × A, cartesian product of A with itself, defined by $(\text{a, b})\simeq(\text{c, d)}$ if ad = bc. Then, the number of ordered pairs of the equivalence class of (3, 2) is:
  1. 4
  2. 5
  3. 6
  4. 7
If $AA^T = I$ and $C$ is skew symmetric matric then $((A^T CA)^{50})^T$ is equal to
$\int\cos^{-1}(\frac{1}{\text{x}})\text{dx}$ equals:
  1. $\text{x}\sec^{-1}\text{x}+\log|\text{x}+\sqrt{\text{x}^2-1}|+\text{c}$
  2. $\text{x}\sec^{-1}\text{x}-\log|\text{x}+\sqrt{\text{x}^2-1}|+\text{c}$
  3. $-\text{x}\sec^{-1}\text{x}-\log|\text{x}+\sqrt{\text{x}^2-1}|+\text{c}$
  4. $\text{None of these}$
The value of ${\sin ^{ - 1}}(\sin \,100) + \,{\cos ^{ - 1}}(\cos \,100) + {\tan ^{ - 1}}\,(\tan \,100) + {\cot ^{ - 1}}(\cot \,100)$
Let $E, F$ and $G$ be three events having probabilities $P ( E )=\frac{1}{8}, P ( F )=\frac{1}{6}$ and $P ( G )=\frac{1}{4}$, and let $P ( E \cap F \cap G )=\frac{1}{10}$.

For any event $H$, if $H ^{ C }$ denotes its complement, then which of the following statements is(are) $TRUE$?

$(A)$ $P \left( E \cap F \cap G ^{ C }\right) \leq \frac{1}{40}$

$(B)$ $P\left(E^C \cap F \cap G\right) \leq \frac{1}{15}$

$(C)$ $P ($E$\cup F \cup G ) \leq \frac{13}{24}$

$(D)$ $P \left( E ^{ C } \cap F ^{ C } \cap G ^{ C }\right) \leq \frac{5}{12}$

The parameter on which the value of the determinant $\left| {\,\begin{array}{*{20}{c}}1&a&{{a^2}}\\{\cos (p - d)x}&{\cos px}&{\cos (p + d)x}\\{\sin (p - d)x}&{\sin px}&{\sin (p + d)x}\end{array}\,} \right|$ does not depend upon
The area bounded by the curve $x=3 y^2-9$ and the line $x=0, y=0$ and $y=1$ is
Let $\alpha \beta \neq 0$ and $A=\left[\begin{array}{ccc}\beta & \alpha & 3 \\ \alpha & \alpha & \beta \\ -\beta & \alpha & 2 \alpha\end{array}\right]$. If $B=\left[\begin{array}{ccc}3 \alpha & -9 & 3 \alpha \\ -\alpha & 7 & -2 \alpha \\ -2 \alpha & 5 & -2 \beta\end{array}\right]$ is the matrix of cofactors of the elements of $A$, then $\operatorname{det}(A B)$ is equal to.
If $\int\frac{\cos8\text{x}+1}{\tan2\text{x}-\cot2\text{x}}\text{ dx}=\text{a}\cos8\text{x}+\text{C},$ then a =
  1. $-\frac{1}{16}$
  2. $\frac{1}{8}$
  3. $\frac{1}{16}$
  4. $-\frac{1}{8}$