31 The average annual snowfall in a certain region is modeled by the
⎛
⎞
π
=
+
⎜
t
⎟
function
S( )
t
20 10
cos
, where S represents the annual snow-
⎝
⎠
5
fall, in inches, and t represents the number of years since 1970.
What is the minimum annual snowfall, in inches, for this region?
In which years between 1970 and 2000 did the minimum amount of
snow fall? [The use of the grid on the next page is optional.]
[16]
Math. B – June ’07