[填空题]
The average daily hours of sunlight, S, during a 129lrr;,g ;;dm qt 5recf-month period in a j 5vgwp lcb)6v- /gp7fparticular town is given by the function
vcpvg bfp j7 )5l6gw-/ $S(t)=\,acos(bt−π)+d$,
where time,t, is measured in months, a and d are constants, and b is measured in degrees.
The graph of $S$ versus t is shown in the diagram below.
1.Find the value of
(1)a =
(2)d =
2.Find the value of b.b = $^{\circ}C$
3.Write down the values of t when the average daily sunlight is 10 hours.
