q-Cosine
The q-Analog of the Cosine function, as advocated by R. W. Gosper, is defined by
where
is a Theta Function and 
is defined via
This is a period
, Even Function of unit amplitude with double and triple angle formulas and addition formulas whichare analogous to ordinary Sine and Cosine. For example,
where
is the q-Sine, and 
is q-Pi. The 
-cosine also satisfies
See also q-Factorial, q-Sine
References
Gosper, R. W. ``Experiments and Discoveries in -Trigonometry.'' Unpublished manuscript.
- Schrage's Algorithm
- Schroeder Stairs
- Schröder-Bernstein Theorem
- Schröder Number
- Schröder's Equation
- Schröder's Method
- Schröter's Formula
- Schur Algebra
- Schur Functor
- Schur Matrix
- Schur Multiplier
- Schur Number
- Schur's Inequalities
- Schur's Lemma
- Schur's Problem
- Schur's Representation Lemma
- Schur's Theorem
- Schwarzian Derivative
- Schwarz-Pick Lemma
- Schwarz Reflection Principle
- Schwarz's Inequality
- Schwarz's Triangle Problem
- Schwarz Triangle
- Schwenk's Formula
- Schönflies Symbol