The Werner formulas are the trigonometric product formulas
 |  |  | (1) |
 |  |  | (2) |
 |  |  | (3) |
 |  |  | (4) |
This form of trigonometric functions can be obtained in the Wolfram Language using the command TrigReduce[expr].
Werner Formulas
See also
Prosthaphaeresis FormulasExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Werner Formulas." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/WernerFormulas.html