Vanishing point line that lies in the plane , which is defined by the equation . Using perspective pinhole projections, a point on projected on the image plane will have coordinates defined as, This is the parametric representation of the image of the line with as the parameter. When it stops at the point on the axis of the image plane. This is the vanishing point corresponding to all parallel lines with slope in the plane . All vanishing points associated with different lines with different slopes belonging to plane will lie on the axis, which in this case is the horizon
Tricritical point more components. It can be shown that three is the "minimum" number of components for which these points can appear. In this case, one may have a two-dimensional region of three-phase coexistence ("F" = 2-3+3 =2) (thus, each point in this region corresponds to a triple point). This region (F=2, P=3) will terminate in two critical lines of two-phase coexistence; these two critical lines (F=1, P=2) may then terminate at a single tricritical point. This point (F=0, P=1) is therefore "twice critical", since it belongs to two critical branches.<br> Indeed, its critical behavior is different from that of a conventional