Physics—Sight Lines: The distance that a person can see from an airplane to the horizon on...

Physics—Sight Lines: The distance that a person can see from an airplane to the horizon on a cloudless day is given by

where x represents the altitude of the plane in feet, and f(x) is the distance that a person can see in miles.

(a) Evaluate f(32,000) and interpret.

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(b) Find the slope of the secant line for x = 36,000 and Δx = 4000 and interpret.