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 which are analogous to ordinary Sine and Cosine. For example,

where is the

**References**

Gosper, R. W. ``Experiments and Discoveries in -Trigonometry.'' Unpublished manuscript.

© 1996-9

1999-05-25