ABSTRACT
Iav m =Iv dm =Iv (i;"P +ayQ + 0 zR)dx /\ dy /\ dz . The boundary OV being positively oriented (normal vector to V pointing outward), we find again the usual Ostrogradski formula:
r PdY/\~+Q~/\dx+Rdx/\dy=J (djvX)d~dT]dsJav ~ meaning that the (outward) flux of vector field X(P,Q,R) through OV is the triple integral of the divergence ofX over V.
