## Laplacian(function, [varlist], [mode])

function
This is defined by the mode parameter as cartesian coordinates (mode=0), cylindrical coordinates (mode=1) or spherical coordinates (mode=2).

[varlist]
This parameter is optional and when not defined uses the following values.
mode=0 : [x, y, z]
mode=1 : [r, Φ, z]
mode=2 : [r, θ, Φ]

When other variables are used these have to be declared in the varlist as [ var1 , var2 , var3 , ...].

[mode]
The default value is 0.

## Description

Returns the Laplacian of the function.

This is normally denoted as Laplacian(F) = ∇2F

## Examples

Laplacian(x^2+y^2+z^2)
Laplacian(x*y/z)
Laplacian(sin(x)*exp(y)/ln(z))
Laplacian(r*sin(@theta)*cos(@phi), 0, 2)
Laplacian(z^2*r*cos(@phi), 0, 1)

## Cartesian coordinates

Laplacian(f(x, y, z))

## Cylindrical coordinates

Laplacian(f(r, @phi, z), 0, 1)

## Spherical coordinates

Laplacian(h(r, @theta, @phi), 0, 2)

## References

http://mathworld.wolfram.com/Laplacian.html
http://en.wikipedia.org/wiki/Laplacian