Question: The number of hours, H, of daylight in Madrid is a function of t, the number of days since the start of the year. Figure shows a one-month portion of the graph of H.
![916_19.jpg](https://secure.tutorsglobe.com/CMSImages/916_19.jpg)
(a) Comment on the shape of the graph. Why does it look like a straight line?
(b) What month does this graph show? How do you know?
(c) What is the approximate slope of this line? What does the slope represent in practical terms?