Partial Differential Equations

ivan gabrovski

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About this app

App Partial Differential Equations
A PDE is an equation involving partial derivatives of an unknown function of several variables (typically space and/or time).
General Form: F(x,y,u,u_dx, u_dy, ...)=0
For a function u(x, y) or u(x, t):
Classification by Order
First order -” contains only first partial derivatives
Second order - most common in physics (heat, waves, potential)
The Three Classical Types (linear, second order)
1. Parabolic heat/diffusion equation:
2. Hyperbolic wave equation:
3. Elliptic Laplace's equation:
The distinction comes from the discriminant in the general form Au_ xx + Bu_xy + Cu_ yy + and so on = 0: parabolic when B squared minus 4AC = 0, hyperbolic when >0, elliptic when <0 ” by analogy with conic sections.
The heat conduction equation (also called the diffusion equation) describes how temperature spreads through a medium over time.
The wave equation describes propagation of disturbances (vibrations, sound, light, water waves) through a medium at a finite speed.
Elliptic equations describe steady-state (time-independent) equilibrium configurations — not evolution over time. The classic example is Laplace's/Poisson's equation.
Main Solution Methods
Separation of variables assumes u(x,t) = X(x)T(t)
Method of characteristics or first-order equations
Integral transforms Fourier, Laplace
Green's functions
Numerical methods - finite differences, finite elements (for cases without closed-form solutions)
The application applies numerical methods for heat, wave and elliptic equations And changes parameters in dialog. Results shows graphically and in parameters.