Respuesta :
Parameterize [tex]S[/tex] by
[tex]\vec s(u,v)=(1-u)v\,\vec\imath+8uv\,\vec\jmath+8(1-v)\,\vec k[/tex]
with [tex]0\le u\le1[/tex] and [tex]0\le v\le1[/tex].
Then the surface element is
[tex]\mathrm dS=\|\vec s_u\times\vec s_v\|\,\mathrm du\,\mathrm dv=8\sqrt{66}\,v\,\mathrm du\,\mathrm dv[/tex]
and the surface integral is
[tex]\displaystyle\iint_Sxy\,\mathrm dS=8\sqrt{66}\int_0^1\int_0^18(1-u)uv^3\,\mathrm du\,\mathrm dv=\boxed{8\sqrt{\dfrac{22}3}}[/tex]
In this exercise we have to use the knowledge of parameterization and integrals to calculate the area needed, so we will find that this corresponds to:
[tex]8\sqrt{\frac{22}{3} }[/tex]
Parameterizing the function given as:
[tex]s(u, v) = (1-u)v+8uv+8(1-v)[/tex]
Knowing that the integration limits will be given by:
[tex]0\leq u\leq 1 \ and \ 0\leq v\leq 1[/tex]
So in this way calculating the surface we will find that it will be:
[tex]dS= 8\sqrt{66} v du dv[/tex]
Now putting all this data together in the integral, we will find that it will correspond to:
[tex]\int\limits \, \int\limits_S {xy} \, dxS\\8\sqrt{66}\int\limits^1_0 \int\limits^1_0 {8(1-u)uv^3} \, dufv\\= 8\sqrt{\frac{22}{3} }[/tex]
See more about parameterizing at brainly.com/question/14770282