Hi,
Can anyone please help with constructing the following proof. I'm not sure how to go about it.

Starting with the Divergence Theorem and two smooth scalar functions
f and g, a closed surface S enclosing a volume V , derive the First Green's formula.
<br />
\int \int (f\nabla g) \cdot ndS = \int \int \int(f\nabla^2g + \nabla f \cdot \nabla g dV