The Arctic Sea ice extent, the area of sea covered by ice, grows over the winter months, typically from November to March. Let F(t) be the Arctic Sea ice extent, in million of square kilometers, as a function of time, t, in days since November 1, 2014. Then F'(t) = 0.073 on January 1, 2015.12
(a) Give the units of the 0.073, and interpret the number in practical terms.

(b) Estimate ΔF between January 1 and January 6, 2015. Explain what this tells us about Arctic Sea ice.