2. Derive the two-dimensional 3rd order (6 node) approximation functions based on Lagrange interpolating polynomials. Assume that 51 12 11 10 90 S13 $16 S10 $14 $15 11 16 15 ns n2 +1 ng 12 13 14 7 n12 n14 17 13 n11 n16 n15 5 6 2
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