Answer Happy

Throughout much of the 20th century, the yearly consumption of electricity in the US increased exponentially at a continuous rate of 9% per year. Assume this trend continues and that the electrical energy consumed in 1900 was 1.3 million megawatt-hours. (a) Write an expression for yearly electricity consumption in million megawatt-hours, E, as a function of time, t, in years since 1900. E(t) = 1.3e0.09 (b) Find the average yearly electrical consumption throughout the 20th century. (Round your answer to the nearest whole number.) 1170 ✓ million megawatt-hours (c) During what year was electrical consumption the closest to the average for the century? 1976 (d) Without doing the calculation for part (c), how could you have predicted which half of the century the answer would be in? If you graph the exponential function E(t), you can see that the average E(t) value occurs at exactly t = 50. Therefore, the answer is at the midpoint of the century. If you graph the exponential function E(t), you can see that the t value such that E(t) equals the average calculated in part (b) lies in the right half of the graph. Therefore, the answer would be in the second half of the century. If you graph the exponential function E(t), you can see that the average E(t) value is in the bottom half of the graph. Therefore, the answer would be in the first half of the century. If you graph the exponential function E(t), you can see that the average E(t) value is in the top half of the graph. Therefore, the answer would be in the second half of the century. If you graph the exponential function E(t), you can see that the t value such that E(t) equals the average calculated in part (b) lies in the left half of the graph. Therefore, the answer would be in the first half of the century.