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 Unpublished manuscript.
- Cover Relation
- Coversine
- Coxeter Diagram
- Coxeter-Dynkin Diagram
- Coxeter Graph
- Coxeter Group
- Coxeter Matrix
- Coxeter's Loxodromic Sequence of Tangent Circles
- Coxeter-Todd Lattice
- Cox's Theorem
- Cramer's Rule
- Cramér Conjecture
- Cramér-Euler Paradox
- Cramér's Theorem
- Craps
- CRC
- Creative Telescoping
- Cremona Transformation
- Cribbage
- Criss-Cross Method
- Criterion
- Critical Line
- Critical Point
- Critical Strip
- Crook