In a convex quadrilateral ABCD, diagonals AC and BD intersect at E, while perpendicular bisectors of AB and CD intersect at F, and those of BC and DA intersect at G. Prove: (1) E, F, and G are collinear, (2) AE:EC = BF:FD, and (3) CG:GD = AF:FB.
If we observe when light source
illuminates the surface of an object
lets say its a sphere(football) ,the area
visible zone decreases as the light source
comes near the surface.So calculate rate of change
visible area when light source is coming
towards the object or moving away
from the object.And in the case of earth
find the equation in function of time
If the light object is coming from space
towards earth, express that expression
in the function of time