5. \( g(x)=\frac{x^{2}}{e^{x}} \)

3. (a) Montrer que pour tout réel \( t \geq 0: t-\frac{t^{3}}{3} \leq \arctan (t) \leq t \) (b) Calculer la limite : \( \lim _{x \rightarrow+\infty} x\left(1-x \arctan \left(\frac{1}{x}\right)\right) \).

\( \left. \begin{array} { l } { \frac { d } { d x } ( \sin ^ { 2 } x ^ { 2 } ) } \\ { \frac { d } { d x } ( \sin x ) ^ { 2 } } \\ { = 2 \cos x } \end{array} \right. \)

Let \( y-x e^{y}=1 \), then \( d y(0)= \)

22. a) If \( f(x)=\frac{|6-x|}{x-6} \), find \( \lim _{x \rightarrow 6+} f(x) \) (if exist.) b) Evaluate: \( \lim _{x \rightarrow 0} \frac{\tan x-\sin x}{x^{3}} \) c) Evaluate: \( \lim _{x \rightarrow 0} \frac{x\left(2^{2}-1\right)}{1-\cos x} \) KMC Note d) Find \( \frac{d x}{d y} \) if \( x^{3}+y^{3}=3 a x^{2} y \) e) What is the derivative of \( \sec ^{-1} x \) with respect to ' \( x \) '.

If \( x^{3}+y^{3}=6 x y \), then find \( \frac{d y}{d x} \) and \( \frac{d^{2} y}{d x^{2}} \)