Esophageal cancer describes the disease where cells that line the esophagus change or mutate and become malignant. These cells grow out of control and form a mass or tumor. There are two main types of esophageal cancer:
Trajectory. A trajectory is the path that a moving object follows through space as a function of time. The object might be a projectile or a satellite, for example. It thus includes the meaning of orbitâthe path of a planet, an asteroid or a comet as it travels around a central mass.
Geometric Definition. Definition: A parabola is the set of points in the plane that are equidistant from a point (the focus) and a line (the directrix.). The following exercise should help convince you that this definition yields the parabolas you are familiar with. Exercise: Given a focus at (0,1) and a directrix y=-1, find the equation of the parabola. How to do it: draw a figure showing a generic point P on the parabola, with coordinates (x,y).