Wolfram Research
Wolfram Math World: Law of Cosines
This page from MathWorld.com gives a good explanation of the Law of Cosines, which relates the lengths of the legs of a triangle to the angles. This site shows how the formula is derived, along with a triangle to clarify variables. Also...
Other
Brown Math: Remembering Trig Identities
Faced with a large number of trigonometric identities, students tend to try to memorize them all. This site the emphasis is on understanding how the functions work and on memorizing only about a half dozen of them - all the others work...
Oswego City School District
Regents Exam Prep Center: Working on a Rescue Team Lab
Your students are part of the Yellowstone National Park rescue team which has just been dispatched to help located a downed plane. How can they effectively use the Law of Sines and the Law of Cosines to assist them in finding the plane?...