Coversine

The coversine is a little-used entire trigonometric function defined by

			(1)
			(2)

where  is the versine and  is the sine.

The coversine can be extended to the complex plane as illustrated above.

Its derivative is given by

(3)

and its indefinite integral by

(4)

REFERENCES:

Abramowitz, M. and Stegun, I. A. (Eds.). Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables, 9th printing. New York: Dover, p. 78, 1972.