City planners model the size of their city using the function A(t)=(-1/50)*t^2+2t+20, where A is measured in square miles and t is the number of years after 2010. How fast will the city be growing when it reaches a size of 38mi^2? Suppose the population density of the city remains constant from year to year at 1000 people/mi^2. Determine the growth rate of the population in 2030.
Why for piecewise function constrains on the variable change to strict? For example