Contributed to the mphowardlab/essential-math repository by developing a new feature that introduces the triple product rule in multivariable calculus, with a focus on its application to thermodynamics and heat capacity. The work involved rigorous mathematical derivation, clear technical writing, and the integration of a practical example to enhance learner understanding. Documentation was authored in Markdown, ensuring accessibility and clarity for contributors and users. The update also included proper attribution for new contributors, reflecting collaborative development practices. No bugs were addressed during this period, with efforts concentrated on expanding core calculus content and improving the pedagogical value of the repository.