$$\color{rgb(0,0,255)}f(x)=x+\sin x$$

$$\color{rgb(127,0,0)}u(x)=x-1$$

$$\color{rgb(0,127,0)}v(x)=x+1$$

$$\color{rgb(127,0,127)}\text{Pour tout r}\acute{e} \text{el }x,u(x) \le f(x) \le v(x)$$

$$\color{rgb(0,0,0)}x$$

$$\color{rgb(0,127,0)}v(x)$$

$$\color{rgb(0,0,255)}f(x)$$

$$\color{rgb(127,0,0)}u(x)$$