Consider the bvp for the steady-state temperature u(x, y, z) in the air space between two infinite (in the y and z directions) stone walls that are perpendicular to the x- axis, and are 5 centimeters apart from each other (i. e., the wall surfaces in contact with the air space are 5 cm, apart), with the first (or left) wall located at x = -1 cm., and the second (or right) wall at x = 4cm., where uy = -10, and u = 100, respectively. temperature is measured in degrees centigrade, and heat energy in calories. you may assume that the two walls are very thick relative to the space between them, e. g., 10 meters thick. (a) mathematically set up the bvp by formally writing down the pde and boundary conditions, and corresponding independent variable domains, with as much mathematical detail as possible to completely specify and write down the bvp.