Answer:
Vertical distance between the valley and the summit = 8062.5 ft
Step-by-step explanation:
Distances above the sea level are denoted by positive notations and below the sea level by negative notation.
Summit of a mountain pass = 8050 (above the sea level)
Valley below the sea level = 12 and half ft = (-12.5) ft
Distance between the summit and the valley = 8050 - (-12.5)
= 8050 + 12.5
= 8062.5 ft
Therefore, Vertical distance = 8062.5 ft will be the answer.
Given that
, we have
, so that

Take the derivative and find the critical points of
:

Take the second derivative and evaluate it at the critical point:

Since
is positive for all
, the critical point is a minimum.
At the critical point, we get the minimum value
.
The correct answer is "all real numbers greater than or equal to 2".
I do believe that those are called numbers