question: public static double cosQuick ( double angle ) { if ( USE_JDK_MATH ) { return STRICT_MATH ? StrictMath . cos ( angle ) : Math . cos ( angle ) ; } return cosTab [ ( ( int ) ( Math . abs ( angle ) * SIN_COS_INDEXER + 0.5 ) ) & ( SIN_COS_TABS_SIZE - 2 ) ] ; }
target:  Quick cosine, with accuracy of about 1.6e-3 (PI/'look-up tabs size') for |angle| &lt; 6588397.0 (Integer.MAX_VALUE * (2*PI/'look-up tabs size')), and no accuracy at all for larger values.