Function and Gradient Values

A solution for the coefficients gives us access to the solution in the three regions. Using the transformation rules for changing from derivatives in Cartesian to derivatives in polar coordinates

we can implement a function, makeWaveFunctionAndGradientDefinition, that sets up definitions for the solution = and the gradient vector nabla=. (We will use the gradient vector to calculate currents associated with the complex-values wave function .)

We also define a function, insideQ, that returns True if the point is inside the left arm, right arm, or center disk.