6. After you eat something containing sugar, the pH or acid level in your mouth changes. This can be modeled by the function below, where L is the pH level and n is the number of minutes that have elapsed 20.4n since eating. L(n) = 6- n2+36 Calculate the instantaneous rate of change at 4 minutes. What does this value represents in this situation.

A 12-inch tall sunflower is planted in a garden and the height of the sunflower increases by 8% per day. What is the 1-day percent change in the height of the sunflower? At any given moment, the height of the sunflower is what percent of its height 1 day prior? What is the 1-day growth factor for the height of the sunflower? Write a function f(t) that determines the height of the sunflower (in inches) in terms of the number of days t since it was planted. What does f(4) mean in the context of this problem? If the sunflower is 23 inches tall, then how many days has the sunflower been growing for?

Suppose that a student carrying a flu virus returns to campus and that four days later fifty students have been infected. Determine the number of infected students as a function time. Assume that the virus spreads at a rate that is proportional to both the number of students that have been infected and the number of students that have not been infected. Also assume that the campus population is 5000 students.

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