The versine or versed sine, versin(θ), is a trigonometric function equal to and 2sin2(?θ). It appeared in some of the earliest trigonometric tables and was once widespread, but it is now little-used.

Versine
Versine
Versine
MDO-j?rjestelm?n kehitt?minen : Case: Versine Oy
An Algorithm for the Curve Versine Measurements on Railway Tracks
On design for railway curve super-high and versine
Dropping response of simple supported PCB under versine stimulation
Research on Calculation Method of Plan Versine in Existing Railway Curve Adjusting
Research on Calculation Method for Railway Planning Versine of Centered Compound Curve
Discussion on the Calculation of the Curve Versine Circular and Its Application in Railway Track Engineering
Application of weighted total least-square adjustment to the versine fitting of the railway curve
Estimation method of short wave length track irregularity with short length chord versine
A new approach for the modelling of track geometry recording vehicles and the deconvolution of versine measurements