Question

Between 1989 and 1998, the population of smalltown, USA ( in thousands) can be modeled by f(x)=.24x^2 -0.96x + 4, where x=0 represents 1989. Based on this model, in what year did the population of small town reach its minimum?

Answer 1

Just use derivatives:

f'(x)= .48x-.96 = 0, x = 2, since the coeff of x^2 is +, this is a minimum

x=0 1989, so x = 2 is 1991! :)