If $f:[-5,5] \rightarrow \mathrm{R}$ is a differentiable function and if $f^{\prime}(x)$ does not vanish anywhere, then prove that $f(-5) \neq f(5).$
It is given that $f:[-5,5] \rightarrow R$ is a differentiable function.
Since every differentiable function is a continuous function, we obtain
a) $f$ is continuous on $[-5,5].$
b) $f$ is continuous on $(-5,5).$
Therefore, by the Mean Value Theorem, there exists $c \in(-5,5)$ such that
$f^{\prime}(c)=\frac{f(5)-f(-5)}{5-(-5)}$
$\Rightarrow 10 f^{\prime}(c)=f(5)-f(-5)$
It is also given that $f^{\prime}(x)$ does not vanish anywhere.
$\therefore f^{\prime}(c) \neq 0$
$\Rightarrow 10 f^{\prime}(c) \neq 0$
$\Rightarrow f(5)-f(-5) \neq 0$
$\Rightarrow f(5) \neq f(-5)$
Hence, proved.
If the function $f(x) = {x^3} - 6{x^2} + ax + b$ satisfies Rolle’s theorem in the interval $[1,\,3]$ and $f'\left( {{{2\sqrt 3 + 1} \over {\sqrt 3 }}} \right) = 0$, then $a =$ ..............
Verify Rolle's theorem for the function $y=x^{2}+2, a=-2$ and $b=2$
Let $\psi_1:[0, \infty) \rightarrow R , \psi_2:[0, \infty) \rightarrow R , f:[0, \infty) \rightarrow R$ and $g :[0, \infty) \rightarrow R$ be functions such that
$f(0)=g(0)=0$
$\Psi_1( x )= e ^{- x }+ x , \quad x \geq 0$
$\Psi_2( x )= x ^2-2 x -2 e ^{- x }+2, x \geq 0$
$f( x )=\int_{- x }^{ x }\left(| t |- t ^2\right) e ^{- t ^2} dt , x >0$
and
$g(x)=\int_0^{x^2} \sqrt{t} e^{-t} d t, x>0$
($1$) Which of the following statements is $TRUE$ ?
$(A)$ $f(\sqrt{\ln 3})+ g (\sqrt{\ln 3})=\frac{1}{3}$
$(B)$ For every $x>1$, there exists an $\alpha \in(1, x)$ such that $\psi_1(x)=1+\alpha x$
$(C)$ For every $x>0$, there exists a $\beta \in(0, x)$ such that $\psi_2(x)=2 x\left(\psi_1(\beta)-1\right)$
$(D)$ $f$ is an increasing function on the interval $\left[0, \frac{3}{2}\right]$
($2$) Which of the following statements is $TRUE$ ?
$(A)$ $\psi_1$ (x) $\leq 1$, for all $x>0$
$(B)$ $\psi_2(x) \leq 0$, for all $x>0$
$(C)$ $f( x ) \geq 1- e ^{- x ^2}-\frac{2}{3} x ^3+\frac{2}{5} x ^5$, for all $x \in\left(0, \frac{1}{2}\right)$
$(D)$ $g(x) \leq \frac{2}{3} x^3-\frac{2}{5} x^5+\frac{1}{7} x^7$, for all $x \in\left(0, \frac{1}{2}\right)$
Mean value theorem $f(b) -f(a) = (b -a) f '(x_1);$ from $a < x_1 < b,$ if $f(x) = 1/x$ then $x_1 = ?$
A value of $c$ for which the conclusion of mean value the theorem holds for the function $f(x) = log{_e}x$ on the interval $[1, 3]$ is