Figure 2-7 Linear Pollution Reduction
Graphing Functions
Different functions have different graphs, and we will see many of these
in subsequent chapters.Figure 2-6 is an example of a relation in which
the two variables move together. When income goes up, consumption
goes up. In such a relation the two variables are positively related to each
other.
Figure 2-7 is an example of variables that move in opposite directions.
As the amount spent on pollution reduction goes up, the amount of
remaining pollution goes down. In such a relation the two variables are
negatively related to each other.
Pollution as a linear function of clean-up expenditure. Between points
and B it costs $2000 to reduce pollution by 1000 tonnes. The cost of
pollution reduction is the same elsewhere on the line. The slope of the
line, −0.5, indicates that any $1 expenditure on pollution clean-up
reduces the amount of pollution by 0.5 tonnes.