6. The length of the day in Boulder (Latitude 40 N) can be modeled approximately by 1(t) = -3cos ( (t+ 10)) + 12 365 where I is given in hours and t is the day of the year. (a) Evaluate (355); fully interpret the result in the context of this problem, including units. (b) Evaluate l'(265); fully interpret the result in the context of this problem, including units. (c) Calculate when I'(t) is largest. Explain