This app is designed for a first classroom encounter with partial differential equations.
The aim is deliberately modest: students should see that a PDE is a rule about how a function changes in different directions.
The app avoids complicated solution methods and focuses on five simple ideas:
a PDE can say that a function does not change in one direction;
integrating one partial derivative leaves an arbitrary function, not just an arbitrary constant;
two derivative rules must be mutually consistent if they are to describe one function;
proposed solutions can be tested by substitution;
transport and wave equations have simple shape-based interpretations.
PDE idea
x-shape G(x)
y-shape F(y)
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Goals
We want to think of seeing PDEs as not just symbols and toward seeing them as directional tests on surfaces and shapes.