1. Use a trapezoidal sum with the four sub-intervals indicated by the data in the table to estimate the definite integral from 0 to 8 of R of t, dt. Using correct units, explain the meaning of your answer in terms of water flow. Give 3 decimal places in your answer.

2. Is there some time t, 0 < t < 8, such that R′(t) = 0? Justify your answer.

3. The rate of water flow R(t) can be estimated by W(t) = ln(t2 + 7). Use W(t) to approximate the average rate of water flow during the 8-hour time period. Indicate units of measure.