The Law of Cosines for an "n"-Dimensional Simplex
IJMEST Volume 39, Number 3, ISSN 0020-739X
Using the divergence theorem technique of L. Eifler and N.H. Rhee, "The n-dimensional Pythagorean Theorem via the Divergence Theorem" (to appear: Amer. Math. Monthly), we extend the law of cosines for a triangle in a plane to an "n"-dimensional simplex in an "n"-dimensional space.
Ding, Y. (2008). The Law of Cosines for an "n"-Dimensional Simplex. International Journal of Mathematical Education in Science and Technology, 39(3), 407-410.