The publisher apologises that upon publication of the article, the second derivative on the right-hand side of equation 3.21 was mistyped and thus presented incorrectly as
![](https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20221027084145807-0450:S002211202200859X:S002211202200859X_eqn1.png?pub-status=live)
The correct equation should be as below
![](https://static.cambridge.org/binary/version/id/urn:cambridge.org:id:binary:20221027084145807-0450:S002211202200859X:S002211202200859X_eqn2.png?pub-status=live)
10 September 2024: Due to technical disruption, we are experiencing some delays to publication. We are working to restore services and apologise for the inconvenience. For further updates please visit our website: https://www.cambridge.org/universitypress/about-us/news-and-blogs/cambridge-university-press-publishing-update-following-technical-disruption
Published online by Cambridge University Press: 27 October 2022
The publisher apologises that upon publication of the article, the second derivative on the right-hand side of equation 3.21 was mistyped and thus presented incorrectly as
The correct equation should be as below