In a particular application involving fluid flow at a rate nz through a circular tube of length L and diameter D, the surface heat flux is known to have a sinusoidal variation with x, which is of the form q"s(x) = q"s;m sin (πx/L). The maximum flux, q"s,m, is a known constant, and the fluid enters the tube at a known temperature, Tm.i, Assuming the convection coefficient to be constant, how do the mean temperature of the fluid and the surface temperature vary with x?