Temperature variation in Ottawa The annual variation in temperature T (in °C) in Ottawa, C...

Temperature variation in Ottawa The annual variation in temperature T (in °C) in Ottawa, Canada, may be approximated by

where t is the time in months and t = 0 corresponds to January 1.

(a) Sketch the graph of T for 0 ≤ t ≤ 12.

(b) Find the highest temperature of the year and the date on which it occurs.