A valve on a storage tank is opened for 4 hours to release a chemical in a manufacturing process. The flow rate R (in liters per hour) at time t (in hours) is given in the table.

(a) Use the regression capabilities of a graphing utility to find a linear model for the points (t, ln R). Write the resulting equation of the form ln R = at + b in exponential form.

(b) Use a graphing utility to plot the data and graph the exponential model.

(c) Use a definite integral to approximate the number of liters of chemical released during the 4 hours.

0 R 425 t 1 240 2 118 3 71 4 36