Let fs r be a finite set. (a) prove that f is closed (b) prove that every point in f is an isolated point.

a) Suppose that F is ordered in ascending order: . Then, the complement of F can be written as

which is the union of a finite number of open intervals, then is an open set. Thus, F is a closed subset of the real numbers.

b) Take an arbitrary element of F, let us say . Now, choose a real number such that

there are not other element of F, because is less that the minimum distance between and its neighbors.

In case that we only consider , and if we only consider .

Then, all points of F are isolated.

Step-by-step explanation:

12,450

Step-by-step explanation: Since the climber descends to meet a fellow climber by 200 ft you are going to subtract so the equation is going to be 12,740-200 ft so what does that equal it equals 12,540 ft because it is only subtracting 740-200 ft so 740-200=540 so your answer would more likely be 12,540 not the negative answer.