Let's consider a code example showing what would be allowed (or not) using different levels of inheritance: 1  class BaseClass {}; void freeStandingFunction(BaseClass* b); class DerivedProtected : protected BaseClass { DerivedProtected() { freeStandingFunction(this); // Allowed } };
Definition of Horizontal Axis. Horizontal means flat or level. Horizontal axis is the x-axis on a graph. The blue number line in the figure below is the x-axis, the horizontal axis.
Then the directrix, being perpendicular to the axis, is a horizontal line and it must be p units away from V. The directrix then is the line y=-p. Consider a point P with coordinates (x,y) on the parabola and let Q be the point on the directrix such that the line through PQ is perpendicular to the directrix.