returns the opposite vector v2 of this , such that the sum of this and v2 equals the null vector . concode_field_sep double x concode_elem_sep double y concode_field_sep Vector2D minus concode_elem_sep Vector2D rotate concode_elem_sep double dot concode_elem_sep double dot concode_elem_sep double cross concode_elem_sep double cross concode_elem_sep Vector2D plus concode_elem_sep boolean almostEquals concode_elem_sep double norm concode_elem_sep double getX concode_elem_sep Vector2D times concode_elem_sep Vector2D transform concode_elem_sep double getY concode_elem_sep boolean isOrthogonal concode_elem_sep boolean isOrthogonal concode_elem_sep Vector2D normalize concode_elem_sep boolean equals concode_elem_sep double x concode_elem_sep Vector2D clone concode_elem_sep Vector2D create concode_elem_sep Vector2D create concode_elem_sep double y concode_elem_sep double angle concode_elem_sep String toString concode_elem_sep Vector2D createPolar concode_elem_sep boolean isColinear concode_elem_sep boolean isColinear
Vector2D function ( ) { return new Vector2D ( - this . x , - this . y ) ; }