A model for the food-price index (the price of a representative "basket" of foods) between 1984 and 1994 is given by the function
Where t is measured in years since midyear 1984, so , and I(t) is measured in 1987 dollars and scaled such that I(3)=100. Estimate to two decimal places the times when food was cheapest and most expensive during the 1984-1994 period.
cheapest at t =
most expensive at t =
You can earn partial credit on this problem.