In a particular application involving fluid flow at a rate m 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(π x/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?