1. Other Models

2. What we have learned Exponential Growth Model  n(t)=n 0 a t, a>1 Exponential Decay Model  n(t)=n 0 a t, 0<a<1

3. Logarithmic Model y = a + b lnt  Growth if b>0  Decay if b<0

4. Logarithmic Model The number of endangered animal species in the United States from 1990 to 2002 can be modeled by y = -119 +164 ln t, 10 ≤ t ≤ 22, where represents the year, with t = 10 corresponding to 1990. During which year did the number of endangered animal species reach 357?

5. pH Value Chemist use the pH value to describe the acidity of a solution. It is given by the formula: pH = - log[H + ], where [H + ] is measured in moles of hydrogen ions per liter in the solution.  Find the pH of a solution with [H + ] = 0.0063 moles per liter.  Find the amount of hydrogen ions [H + ] in moles per liter of a solution with pH = 6.6.

6. Logistic Model Growth Model y  a, as t  ∞ Grows fastest when y=a/2

7. Logistic Model On a college campus of 5000 students, one student returns from vacation with a contagious and long- lasting flu virus. The spread of the virus is modeled by How many students will be infected after 5 days? At what time is the flu spreading at the fastest rate? The campus will close if more than 55% of students are infected. After how many days will the campus close?

8. Irregular Models The relationship between the price (p) and the demand (d) for a hand-held electronic organizer is given by the demand equation: Find the price when the demand is 800 units. Find the demand if the price is set to be $1000 per unit.

9. Demand for Carb is banned in Texas Fin…