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An elliptic partial differential equation is a general partial differential equation of second order of the form : that satisfies the condition : (Assuming implicitly that . ) Just as one classifies conic sections and quadratic forms based on the discriminant , the same can be done for a second-order PDE at a given point. However, the discriminant in a PDE is given by due to the convention (discussion and explanation here). The above form is analogous to the equation for a planar ellipse: : , which becomes (for : ) : : , and . This resembles the standard ellipse equation: In general, if there are ''n'' independent variables ''x''1, ''x''2 , ..., ''x''''n'', a general linear partial differential equation of second order has the form : , where L is an elliptic operator. For example, in three dimensions (x,y,z) : : which, for completely separable u (i.e. u(x,y,z)=u(x)u(y)u(z) ) gives : This can be compared to the equation for an ellipsoid; == See also == * Elliptic operator * Hyperbolic partial differential equation * Parabolic partial differential equation *PDEs of second order, for fuller discussion 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「elliptic partial differential equation」の詳細全文を読む スポンサード リンク
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