question: public static final BigInteger determinant ( BigInteger p_x_1 , BigInteger p_y_1 , BigInteger p_x_2 , BigInteger p_y_2 ) { BigInteger tmp1 = p_x_1 . multiply ( p_y_2 ) ; BigInteger tmp2 = p_x_2 . multiply ( p_y_1 ) ; return tmp1 . subtract ( tmp2 ) ; }
target:  calculates the determinant of the vectors (p_x_1, p_y_1) and (p_x_2, p_y_2)