MCQ
If $\text{f}(\text{x})=\text{e}^{\text{x}}\sin\text{x}$ in $[0,\pi],$ then $c$ in Rolle's theorem is :
  • A
    $\frac{\pi}{6}$
  • B
    $\frac{\pi}{4}$
  • C
    $\frac{\pi}{2}$
  • $\frac{3\pi}{4}$

Answer

Correct option: D.
$\frac{3\pi}{4}$
$\text{f}(\text{x})=\text{e}^{\text{x}}\sin\text{x}$
$\text{f}\ '(\text{x})=\text{e}^{\text{x}}\cos\text{x}+\text{e}^{\text{x}}\sin\text{x}$
$\text{f}\ '(\text{c})=0$
$\text{e}^\text{c}(\cos\text{c}+\sin\text{c})=0$
$\cos\text{c}+\sin\text{c}=0$
$\cos\text{c}=-\sin\text{c}$
$\tan\text{c}=-1$
$\text{c}=\frac{3\pi}{4}\in(0,\pi)$

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 $a$ and $\mathrm{b}$ respectively be the points of local maximum and local minimum of the function $f(x)=2 x^{3}-3 x^{2}-12 x .$ If $A$ is the total area of the region bounded by $\mathrm{y}=\mathrm{f}(\mathrm{x})$, the $\mathrm{x}$-axis and the lines $x=a$ and $x=b$, then $4 A$ is equal to ..... .
Let $X=\left\{(x, y) \in \mathbb{Z} \times \mathbb{Z}: \frac{x^2}{8}+\frac{y^2}{20}<1\right.$ and $\left.y^2<5 x\right\}$. Three distinct points $P, Q$ and $R$ are randomly chosen from $X$. Then the probability that $P, Q$ and $R$ form a triangle whose area is a positive integer, is
Let $\text{f}(\text{x})=\text{x}^3+\text{a}\text{x}^2+\text{b}\text{x}+5\sin^2\text{x}$ be an increasing function on $R$. Then, $a$ and $b$ satisfy :
Let $\vec{a}=-\hat{i}-\hat{k}, \vec{b}=-\hat{i}+\hat{j}$ and $\vec{c}=\hat{i}+2 \hat{j}+3 \hat{k}$ be three given vectors. If $\vec{r}$ is a vector such that $\vec{r} \times \vec{b}=\vec{c} \times \vec{b}$ and $\vec{r} \cdot \vec{a}=0$, then the value of $\vec{r} \cdot \vec{b}$ is
Solution of the differential equation $\frac{{dy}}{{dx}}\tan y = \sin (x + y) + \sin (x - y)$ is
Let $\alpha$ be a root of the equation $x^{2}+x+1=0$ and the matrix $A=\frac{1}{\sqrt{3}}\left[\begin{array}{ccc}{1} & {1} & {1} \\ {1} & {\alpha} & {\alpha^{2}} \\ {1} & {\alpha^{2}} & {\alpha^{4}}\end{array}\right],$ then the matrix $\mathrm{A}^{31}$ is equal to
The value of $ \left( {{{\tan }^{ - 1}}\pi + {{\tan }^{ - 1}}\left( {\frac{1}{\pi }} \right)} \right) + {\tan ^{ - 1}}\sqrt 3 - {\sec ^{ - 1}}( - 2)$ is equal to
$f : R \rightarrow  (-1,1), f(x) = \frac{e^x - 1}{e^x + 1}$ is
The maximum value of $\mathrm{Z}=x+3 y$ subject to the constraints $2 x+y \leq 20, x+2 y \leq 20$ $x \geq 0, y \geq 0$ is $....$
The least number of times a fair coin must be tossed so that the probability of getting at least one head is at least $0.8,$ is :