It could be shown that the shape function matrix for this tetrahedron element is of the following form of a (12x3) matrix: N 0 0 0 0 N3 0 0 N 00N3 0 N0 N 0 and the S matrix for a three-dimensional finite element is: N = B = b 0 0 0 0 N N N 0 0 N 0 0 / 0 0 a/z 0 /z / / 0 a/az a/ay a/ax 0 Given that B = SN, write down, in terms of N, (i=1,2,3,4) and the partial differential operators (i.e. a/ax, a/ay and a/az), the mathematical form of the matrix elements b, C, d3 and d4 in the following B matrix: 0 0 b 0 0 C1 0 \d S = /a/ax 0 C1 0 d 0 b 0 C2 d C 0 0bd 0 C2 0 d 0 0 C3 0 0 0 0 N 0 N3 0 0 N 0 b3 0 0 0 C3 0 b d C 0 b d3 0 0 0 0 0 b4 0 0 0 0 0 C4 d3 0 0 b3 0 C4 b4 d3 C3 0 d4 0 b3 d4 0 d4 0 C4 b4