Combining equations (7.1.24) and (7.1.26), and making use of the first two terms of formula (D.9) in Appendix D, show that, as \(T\) approaches \(T_{c}\) from above, the parameter \(\alpha(=-\ln z)\) of the ideal Bose gas assumes the form

\[
\alpha \approx \frac{1}{\pi}\left(\frac{3 \zeta(3 / 2)}{4}ight)^{2}\left(\frac{T-T_{c}}{T_{c}}ight)^{2}
\]