Question

The rate at which the world's oil is being consumed in continuously increasing. Suppose the rate of oil consumption (in billions of barrels per year) is given by the function r=f(t), where t is measure in years and t=0 is the start of 2004

(a) Write a definite integral which represents the total quantity of oil used between the start of 2004 and the start of 2009

(b) Suppose . Using a left-hand sum with five subdivisions, find an approximate value for the total quantity of oil used between the start of 2004 and the star of 2009.

(c) Interpret each of the five terms in the sum f