Exercises

Problem 1

Verify that u(x,y)=Exp[x] Cos[y] satisfies Laplace's equation. Use the information on the Cauchy-Riemann equations to find the "stream function" and plot the equipotential curves and the stream lines.

Problem 2

Verify that u(x,y)=1/6 x^4 - x^2 y^2 + 1/6 y^4 satisfies Laplace's equation. Find the stream function and plot the equipotential curves and the streamlines. Hint: Where is this in the list of polynomial solutions?

Problem 3

Why can't we use the Cauchy-Riemann equations to find the stream function for the potential u(x,y)=x^2 y - x y^2 ?

Problem 4

Find the stream function and plot the equipotential curves and the streamlines for u(x,y)=log[sqrt(x^2 + y^2)].
You may need the PlotPoints option to avois jagged equipotentials and streamlines.

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