The city of New Orleans is located at latitude 30oN. Use Figure 9 to find a function

Question:

The city of New Orleans is located at latitude 30oN. Use Figure 9 to find a function that models the number of hours of daylight at New Orleans as a function of the time of year. To check the accuracy of your model, use the fact that on March 31 the sun rises at 5:51AM and sets at 6:18 PM in New Orleans.