Figure 4From: The divergence theorem of a triangular integralTwo kinds of the finite area element of a lower-left piece. Two kinds of finite area element vectors Δ k 2 σ k , j → and Δ j 2 σ k , j → in (3.4) shown in Figure 3 are introduced as </p><p></p><p> for j=1,2,…,k and k=1,2,…,n.Back to article page