3.39 The diagram shows a conical section fabricated from pure aluminum. It is of circular cross section having diameter D = ax2, where a = 0.5 m³/2. The small end is located at x₁ = 25 mm and the large end at x2 = 125 mm. The end temperatures are T₁ = 600 K and T₂ = 400 K, while the lateral surface is well insulated. T2 x2 (a) Derive an expression for the temperature distribution T(x) in symbolic form, assuming one-dimensional conditions. Sketch the temperature distribution. (b) Calculate the heat rate qx.