In a hardening process, a stainless steel plate with a thickness of 50 mm (\rho = 8238 kg/m^3, cₚ = 468 J/kg·\deg C, k = 13.4 W/m·\deg C, and \alpha = 3.48 \times 10⁻⁶ m^2/s) and an initial temperature of 230 \deg C is heated again in a furnace. The uniform ambient temperature inside the furnace is 1000 \deg C, and the convective heat transfer coefficient is 215 W/m^2·\deg C. If the plate is left for 200 seconds to cool, determine the temperature at the center and the edges.