Laplacian: Difference between revisions

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imported>Gemma E. Mason
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The Laplacian is a differential operator of the form<br />
{{subpages}}
The''' Laplacian''' is a differential operator of the form<br />
<math>\sum_{i}\frac{\partial^{2}}{\partial x_{i}^{2}}</math><br />
<math>\sum_{i}\frac{\partial^{2}}{\partial x_{i}^{2}}</math><br />
where <math>x_{i}</math> are Cartesian (that is, rectangular) co-ordinates.  The Laplacian is usually denoted by the symbol <math>\Delta</math> or written as the gradient squared <math>\nabla^{2}</math>.
where <math>x_{i}</math> are [[Cartesian coordinates]].  The Laplacian is usually denoted by the symbol <math>\Delta</math> or written as the gradient squared <math>\nabla^{2}</math>.


In [[cylindrical coordinates]], the Laplacian takes the form<br />
In [[cylindrical coordinates]], the Laplacian takes the form<br />
<math>\frac{1}{\rho}\frac{\partial}{\partial \rho}\bigl(\rho\frac{\partial}{\partial\rho}\bigr)+\frac{1}{\rho^{2}}\frac{\partial^{2}}{\partial\phi^{2}}+\frac{\partial^{2}}{\partial z^{2}}</math><br />
<math>\frac{1}{\rho}\frac{\partial}{\partial \rho}\bigl(\rho\frac{\partial}{\partial\rho}\bigr)+\frac{1}{\rho^{2}}\frac{\partial^{2}}{\partial\phi^{2}}+\frac{\partial^{2}}{\partial z^{2}}</math><br />


In [[spherical co-ordinates]], the Laplacian is<br/>
In [[spherical coordinates]], the Laplacian is<br/>
<math>\frac{1}{\rho^{2}}\frac{\partial}{\partial \rho}\bigl(\rho^{2}\frac{\partial}{\partial\rho}\bigr)+\frac{1}{\rho^{2}\mathrm{sin}\theta}\frac{\partial}{\partial\theta}\bigl(\mathrm{sin}\theta\frac{\partial}{\partial\theta}\bigr)+\frac{1}{\rho^{2}\mathrm{sin}^{2}\theta}\frac{\partial^{2}}{\partial\phi^{2}}</math>
<math>\frac{1}{\rho^{2}}\frac{\partial}{\partial \rho}\bigl(\rho^{2}\frac{\partial}{\partial\rho}\bigr)+\frac{1}{\rho^{2}\mathrm{sin}\theta}\frac{\partial}{\partial\theta}\bigl(\mathrm{sin}\theta\frac{\partial}{\partial\theta}\bigr)+\frac{1}{\rho^{2}\mathrm{sin}^{2}\theta}\frac{\partial^{2}}{\partial\phi^{2}}</math>

Latest revision as of 21:40, 3 September 2010

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The Laplacian is a differential operator of the form

where are Cartesian coordinates. The Laplacian is usually denoted by the symbol or written as the gradient squared .

In cylindrical coordinates, the Laplacian takes the form

In spherical coordinates, the Laplacian is