Prove th set then at every open set can be written as the union of a collection of open intervals. that is, prove that if u is an open where j is some index set and i, is an open interval for all j e j.

An airplane is flying at an elevation of 5150 ft, directly above a straight highway. two motorists are driving cars on the highway on opposite sides of the plane, and the angle of depression to one car is 35 ̊ and to the other is 52 ̊. how far apart are the cars?