For fluids with \(\operatorname{Pr}<1\) the velocity profile is assumed to be a cubic for \(y<\delta\) and a constant equal to 1 for \(\delta1\).

\[\frac{3}{10} \Delta^{2}-\frac{3}{10} \Delta+\frac{2}{15}-\frac{3}{140} \frac{1}{\Delta^{2}}+\frac{1}{180} \frac{1}{\Delta^{3}}=\frac{37}{315} \frac{1}{\operatorname{Pr}}\]

Evaluate and plot \(\Delta\) and the corresponding value of \(N u\) for various values of \(P r\).