- A$4\left(e^{4}+1\right)$
- B$2\left(2 e ^{4}+1\right)$
- C$4 e ^{4}$
- ✓$2\left(2 e ^{4}-1\right)$
$g(x)=\left\{\begin{array}{lll}x^{2}+k_{1} x & ; & x<0 \\ 4 x+k_{2} & ; & x \geq 0\end{array}\right\}$
$g(f(x))=\left\{\begin{array}{lll}f(x)^{2}+k_{1} f(x) & ; & f(x)<0 \\ 4 f(x)+k_{2} & ; & f(x) \geq 0\end{array}\right\}$
$g(f(x))=\left\{\begin{array}{ccc}(x+3)^{2}+k_{1}(x+3) & ; & x<-3 \\ (x+3)^{2}-k_{1}(x+3) & ; & -3 \leq x<0 \\ 4 e^{x}+k_{2} & ; & x>0\end{array}\right\}$
check continuity at $x=0$
${gof}$ $(0)= g \left( f \left(0^{-}\right)\right)= g \left( f \left(0^{+}\right)\right)$
$4+ k _{2}=9-3 k _{1}=4+ k _{2}$
$3 k _{1}+ k _{2}=5$
$( g ( f ( x )))^{\prime}=\left\{\begin{array}{ccc}2( x +3)+ k _{1} & ; & x <-3 \\ 2( x +3)- k _{1} & ; & -3 \leq x <0 \\ 4 e ^{ x } & ; & x \geq 0\end{array}\right\}$
$6- k _{1}=4$
$k _{1}=2$
$\therefore k _{1}=2, k _{2}=-1$
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$f(0)=g(0)=0$
$\Psi_1( x )= e ^{- x }+ x , \quad x \geq 0$
$\Psi_2( x )= x ^2-2 x -2 e ^{- x }+2, x \geq 0$
$f( x )=\int_{- x }^{ x }\left(| t |- t ^2\right) e ^{- t ^2} dt , x >0$
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 $x \in\left(0, \frac{1}{2}\right)$