Let be the level of lake Malawi’s water at a fixed
location as a function of the date in the year
2016.
The date is measured from January
1, and the level is measured in
centimeters above or below the mark
set on January 1.
Given that the lake is filled by rain that falls between
November and April
and that the Shire River is the sole outlet,
which of the following is a possible graph of ?
