heat transfer/heat loss from pipe

A heat pipe figure is given below. At the center of the pipe, a hot gas stream flow through. The hot gas stream temperature is 600K, and the pipe wall is very thin. The heat pipe is coated with insulation of two different materials, X(kX=2.4W/mK) and Y(kY=0.4W/mK) to avoid heat loss. You can assume the interface between X and Y has an infinite contact resistance and the wall temperature is equal to the hot gas stream temperature. In addition, the heat pipe's outer surface is exposed to air for which T=298K and h=25W/m2K.(r1=40mm and r2=120mm) Consider the given information above and answer the following questions. a) Determine the temperature profile equation of the pipe. b) For the prescribed conditions, what is the total heat loss from the pipe? What are the outer surface temperatures Ts,2(X) and Ts,2(Y)