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Laplacian

Laplacian[f]
gives the Laplacian, 2f, of the scalar function or vector field f in the default coordinate system.
Laplacian[f, coordsys]
gives the Laplacian of f in the coordinate system coordsys.
Needs["VectorAnalysis`"]
Laplacian of a function in Cartesian coordinates:
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Needs["VectorAnalysis`"]
Verify that a function is harmonic:
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Needs["VectorAnalysis`"]
Expression for the Laplacian in cylindrical coordinates:
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