function kernelCosf( x ) {
	return addon( x );
}
Computes the cosine of a number on \\( \[-\pi/4, \pi/4] \\) in single-precision floating-point format, where \\( \pi/4 \approx 0.785398164 \\).

@private
@param {number} x - input value (in radians, assumed to be bounded by ~pi/4 in magnitude)
@returns {number} cosine

@example
var v = kernelCosf( 0.0 );
// returns ~1.0

@example
var v = kernelCosf( 3.141592653589793/6.0 );
// returns ~0.866

@example
var v = kernelCosf( 0.785 );
// returns ~0.707

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