Check Divergence Theorem on Unit Cube

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Saladsamurai
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Homework Statement


Check the Divergence Theorem [itex]\int_V(\nabla\cdot\bold{v})\,d\tau=\oint_S\bold{v}\cdot d\bold{a}[/itex]

using the function [itex]\bold{v}=<y^2, 2xy+z^2, 2yz>[/itex] and the unit cube below.
Photo1-1.jpg


Now when I calculate the divergence I get
[itex](\nabla\cdot\bold{v})=2y+2x+2y[/itex]

but Griffith's says that it is 2(x+y)

before I continue, I need to know what the heck I am missing?
 
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Saladsamurai said:
Now when I calculate the divergence I get
[itex](\nabla\cdot\bold{v})=2y+2x+2y[/itex]
How did you get that? You should have [tex]\frac{\partial v_x}{\partial x} + \frac{\partial v_y}{\partial y} + \frac{\partial v_z}{\partial z}[/tex]. Check your first term [tex]\frac{\partial v_x}{\partial x}[/tex].
 
Defennder said:
How did you get that? You should have [tex]\frac{\partial v_x}{\partial x} + \frac{\partial v_y}{\partial y} + \frac{\partial v_z}{\partial z}[/tex]. Check your first term [tex]\frac{\partial v_x}{\partial x}[/tex].

Oh man. Thanks Defennder. I am a retard :smile: