function versin( x ) {
	return 1.0 - cos( x );
}
Computes the versed sine.

@param {number} x - input value (in radians)
@returns {number} versed sine

@example
var v = versin( 0.0 );
// returns 0.0

@example
var v = versin( 3.141592653589793/2.0 );
// returns ~1.0

@example
var v = versin( -3.141592653589793/6.0 );
// returns ~0.13397

@example
var v = versin( NaN );
// returns NaN