$fR{e}_{\sqrt[\phantom{2}]{A}}=[(\frac{3\mathrm{.}44}{\sqrt[\phantom{2}]{L^{+}}}{)}^2+(\frac{12}{\sqrt[\phantom{2}]{}(1+[1-\frac{192}{{}^5}tanh(\frac{}{2})])}{)}^2{]}^{\frac{1}{2}}$

Starting with this equation, and noting that when the flow becomes developed the contribution of the developing and developed terms are equal, derive the following expression for hydrodynamic entrance length

$L_h^{+}=0\mathrm{.}0822(1+{)}^2[1-\frac{192}{{}^5}tanh(\frac{}{2}){]}^2$

I can't plug it in right but it should be $193$epsilon above too like in the first equation.