In Asia over the years 1980–2000, sulfur dioxide emissions due to the burning of fossil...

In Asia over the years 1980–2000, sulfur dioxide emissions due to the burning of fossil fuels can be approximated by the equation

where y represents the sulfur dioxide emissions (in millions of tons) for the year t, with t = 0 corresponding to 1980.

(a) Use a graphing utility to graph the equation in the viewing rectangle [0, 25, 5] by [0, 60, 20]. According to the graph, sulfur dioxide emissions are increasing. What piece of information in the equation tells you this even before looking at the graph?

(b) Assuming that this equation remains valid, estimate the year in which sulfur dioxide emissions in Asia might exceed 65 million tons per year. Note: Rapid growth in Asian economies resulted in 75 million tons in 2000.