A second-order equation: where (i, j = 1, 2) and f are given functions of position (x, y) in a…


A second-order equation:

where  (i, j = 1, 2) and f are attached functions of position (x, y) in a two-dimensional territory and Uo and to are known functions on portions r1, and r2 of the designation r: r 1 +r 2 = r.