<div class="exercice"><span class="exercice"> Exercices :</span>
Calculons le flux du champ \(F(x,y,z) = (x , y , 0))  travers la sphre \calS
paramtre comme auparavant. 

Ce champ est parallle au plan \(xOy). On a 
<center> \(\int\!\!\int _{\mathcal S} F \cdot \vec{dN}= \int_0^{2\pi}\int_{-\pi/2}^{\pi/2} F\cdot \vec{OM}
cos(\varphi) d\varphi d\theta)</center>
<center>= \( \int_0^{2\pi}\int_{-\pi/2}^{\pi/2} (x^2+y^2)
\cos(\varphi) d\varphi d\theta)</center>
<center>= \( \int_0^{2\pi}\int_{-\pi/2}^{\pi/2}
\cos^3(\varphi) d\varphi d\theta)=\(
2\pi \int_{-\pi/2}^{\pi/2}
\cos^3(\varphi) d\varphi= 2\pi/3)</center>
</div>


<div class="exercice"><span class="exercice"> Exercices :</span>

<ul><li>\exercise{cmd=new&module=U2/analysis/oefintsurf.fr&exo=flux1
}{Calcul de flux}
</li>
<li>
\exercise{cmd=new&module=U2/analysis/oefintsurf.fr&exo=flux2
}{Calcul de flux II}
</li>
<li>
\exercise{cmd=new&module=U2/analysis/oefintsurf.fr&exo=fluxsurf
}{Paramtrisation d'une surface et calcul de flux}
</li>
</ul>

</div>