Z00059. The number of  hours of daylight, H, on day t of any given year (on January 1, t = 1) in a particular city can be modeled by the function 

(a) March 19, the 78th day of the year, is the spring equinox. Find the number of hours of daylight in the city on this day.

(b) June 19, the 170th day of the year, is the summer  solstice, the day with the maximum number of hours of daylight. Find the number of hours of daylight in the city on this day.

(c) December 19,  the 353rd day of the year, is the winter solstice,  the day with the minimum number of hours of daylight. Find the number of hours of daylight in the city on this day.