Consider a large plane wall of thickness L=0.4 m, thermal conductivity k =1.8 W/m·°C, and surface area A= 30 m2. The left side of the wall is maintained at a constant temperature of T1=90°C while the right side loses heat by convection to the surrounding air at T=25°C with a heat transfer coefficient of h=24 W/m2·°C. Assuming constant thermal conductivity and no heat generation in the wall, (a) express the differential equation and the boundary conditions for steady one-dimensional heat conduction through the wall, (b) obtain a relation for the variation of temperature in the wall by solving the differential equation, and (c) evaluate the rate of heat transfer through the wall.