In Exercises sketch the appropriate curves. A calculator may be used.

The equation in Exercise 83 can be used for the number of hours of daylight at 40°S latitude with the appropriate change. Explain what change is necessary and determine the proper equation. Sketch the graph. (This would be appropriate for southern Argentina and Wellington, New Zealand.)

Data from Exercises 83

At 40°N latitude the number of hours h of daylight each day during the year is approximately h = 12.2 + 2.8 sin [π/6 (x − 2.7)],  where x is measured in months (x = 0.5 is Jan. 15, etc.). Sketch the graph of h vs. x for one year. (Some of the cities near 40°N are Philadelphia, Madrid, Naples, Ankara, and Beijing.)