Start with Equation IVb.2.8 and obtain Equation IVb.2.9. For this purpose, first ignore the…

Start with Equation IVb.2.8 and obtain Equation IVb.2.9. For
this purpose, first ignore the non-linear term compared with the two dominant
terms. Then substitute for the velocity and temperature profiles. To develop
the integral, consider a case where the hydrodynamic boundary layer is thicker
than the thermal boundary layer (thus the integral is zero for y > _’).
Arrange the result in terms of _ = _’/_ and ignore _ 4.