The total proft (in dollars) from the sale of \( x \) skateboards is \( P(x)=40 x-0.1 x^{2}-240,0 \leq x \leq 100 \). (A) Find the exact profit from the sale of the 21 st skateboard. (B) Use the marginal proft to approximate the profit from the sale of the 21 st skateboard. (A) The exact profit from the sale of the 21 st skateboard \( \$ \square \).

Soit \( f \) la fonction définie sur \( \mathbb{R}^{+} \operatorname{par} f(x)=\frac{2 \sqrt{x}}{x+1} \) Monter que \( f \) est majoréeqar 1. \( f \) est-elle bornée? Justifier votre réponse.

\( f : R ^ { 2 } \rightarrow R , f ( x , y ) = 2 x ^ { 2 } + 3 x y + 4 y ^ { 2 } - 5 x + 2 y + 2024 \)

\( \frac{D y}{D x} \) si \( 4 x \sqrt{y}-\operatorname{sen} \sqrt{x y}+\frac{3^{x}}{y}=y+10 x \)

2. Clase 2. Encontrar las antiderivadas de: \( \begin{array}{l}\text { 1) } \mathrm{F}(\mathrm{x})=\frac{1}{x^{3}} \\ \text { 2) } \mathrm{G}(\mathrm{y})=y^{3}\left(2 y^{2}-3\right) \\ \text { 3) } \mathrm{P}(\mathrm{x})=5 \cos (2 x)-4 \tan \left(\frac{1}{2} x\right) \\ \text { 4) } \mathrm{F}(\mathrm{x})=3 x^{2} e^{2 x}\end{array} \)

\( y ^ { \prime \prime } - y ^ { \prime } - 2 y = x e ^ { 2 u } - e ^ { 2 u } \sin ( 2 x ) \)