Example 4.  Solve Laplace's equation over the square where the boundary conditions are  
    Top:       180  
    Left:         80  
    Bottom:   20  
    Right :        0  

Solution 4.

Suppose that the orientation refers to the "standard" the x-y plane. After we graph the solution we can "modify" the labels in the tick marks to suit our fancy.

Next, solve it.

Plot the solution. Change the axes labels to "x" and "y" and manually supply the tick marks that correspond to these labels.

(c) John H. Mathews 2004