The function, , gives the dollar value of a savings bond  years after the bond was purchased. The graph of  is shown.

1. What is ? What does it mean in this situation?
2. What is ? What does it mean in this situation?
3. When is ? What does this mean in this situation?

Graph of function, origin O. Horizontal axis, from 0 to 10, by 1's, labeled time, years since purchase. Vertical axis, from 0 to 1,800, by 100's, labeled value, dollars. Line starts at 0 comma 1000, passes approximately through 1 comma 1050, 2 comma 1100, 3 comma 1150, 4 comma 1215, 5 comma 1275, 6 comma 1340, 7 comma 1400, 8 comma 1475, 9 comma 1550, 10 comma 1625.  

Technology required. A function, , gives the number of stray cats in a town  years since the town started an animal control program. The program includes both sterilizing stray cats and finding homes to adopt them. An equation representing  is .

1. What is the value of when is 0? Explain what this value means in this situation.
2. What is the approximate value of when is ? Explain what this value means in this situation.
3. What does the number tell you about the stray cat population?
4. Use technology to graph for values of between 0 and 4. What graphing window allows you to see values of that correspond to these values of ?

Function gives the amount of a drug in a dog's body, in milligrams,  hours since the veterinarian administered it. The equation  defines this function.

1. What does the fraction mean in this situation?
2. Sketch a graph of .
3. What are the domain and range of ? Explain what they mean in this situation.

The dollar value of a moped is a function of the number of years, , since the moped was purchased. The function, , is defined by the equation .

What is the best choice of domain for the function, ?

A patient receives 1,000 mg of a medicine. Each hour, of the medicine in the patient's body decays. 

The trees in a forest are suffering from a disease. The population of trees, , in thousands, is modeled by the equation , where is the number of years since 2000.

1. What was the tree population in 2001? What about in 1999?
2. What does the number in the equation for tell you about the population?
3. What is the last year when the population was more than 250,000? Explain how you know.

1. Is the birth date, , a function of the student, ?
2. Is the student, , a function of the birth date, ?

Mai wants to graph the solution to the inequality on a number line. She solves the equation for and gets .