# 2: Classiﬁcation of Partial Diﬀerential Equations

- Page ID
- 8311

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- 2.1: Examples of PDE
- Partial differential equations occur in many different areas of physics, chemistry and engineering.

- 2.2: Second Order PDE
- Second order P.D.E. are usually divided into three types: elliptical, hyperbolic, and parabolic.

- 2.3: More than 2D
- In more than two dimensions we use a similar definition, based on the fact that all eigenvalues of the coefficient matrix have the same sign (for an elliptic equation), have different signs (hyperbolic) or one of them is zero (parabolic)