In a certain city the number of hours of daylight on day t (where t is the number of days after January 1) is modeled by the function
n(2π (t-80)).
365
(a) Which days of the year have about 9 h of daylight? (Enter your answers as a comma-separated list.)
L(t) = 11+ 2.81 sin

(b) How many days of the year have more than 9 h of daylight?