Consider a large plane wall of thickness l 0.21 m, thermal conductivity k 2.5 w/m k, and surface area a 24 m2. the left side of the wall is subjected to a heat flux of 350 w/m2 while the temperature at that surface is measured to be 60 c assuming steady one-dimensional heat transfer, (a) obtain the finite difference formulation for the four nodes and b) determine the temperature of the wall by solving those equations