The table below lists the NBA championship winners for the years 2001 to 2012.
Year
Winner
2001
LA Lakers
2002
LA Lakers
2003
San Antonio Spurs
2004
Detroit Pistons
2005
San Antonio Spurs
2006
Miami Heat
2007
San Antonio Spurs
2008
Boston Celtics
2009
LA Lakers
2010
LA Lakers
2011
Dallas Mavericks
2012
Miami Heat
Consider the relation in which the domain values are the years 2001 to 2012 and the range is the corresponding winner. Is this relation a function? Explain why or why not.
Consider the relation where the domain values are the winners and the range is the corresponding years. Is this relation a function? Explain why or why not.
a. Yes, because there is only one winner for each year. b. No, because there are three teams that won more than once during the years 2001 to 2012.
[T] A rental car company rents cars for a flat fee of $20 and an hourly charge of $10.25. Therefore, the total cost
to rent a car is a function of the hours
the car is rented plus the flat fee.
Write the formula for the function that models this situation.
Find the total cost to rent a car for 2 days and 7 hours.
Determine how long the car was rented if the bill is $432.73.
[T] A vehicle has a 20-gal tank and gets 15 mpg. The number of miles
N that can be driven depends on the amount of gas
x in the tank.
Write a formula that models this situation.
Determine the number of miles the vehicle can travel on (i) a full tank of gas and (ii) 3/4 of a tank of gas.
Determine the domain and range of the function.
Determine how many times the driver had to stop for gas if she has driven a total of 578 mi.
a.
b. i.
therefore, the vehicle can travel 300 mi on a full tank of gas. Ii.
therefore, the vehicle can travel 225 mi on 3/4 of a tank of gas. c. Domain:
range:
d. The driver had to stop at least once, given that it takes approximately 39 gal of gas to drive a total of 578 mi.
[T] The volume
V of a sphere depends on the length of its radius as
Because Earth is not a perfect sphere, we can use the
mean radius when measuring from the center to its surface. The mean radius is the average distance from the physical center to the surface, based on a large number of samples. Find the volume of Earth with mean radius
m.
[T] A certain bacterium grows in culture in a circular region. The radius of the circle, measured in centimeters, is given by
where
t is time measured in hours since a circle of a 1-cm radius of the bacterium was put into the culture.
Express the area of the bacteria as a function of time.
Find the exact and approximate area of the bacterial culture in 3 hours.
Express the circumference of the bacteria as a function of time.
Find the exact and approximate circumference of the bacteria in 3 hours.
a.
b. Exact:
approximately 95 cm
2 c.
d. Exact:
approximately 35 cm
[T] An American tourist visits Paris and must convert U.S. dollars to Euros, which can be done using the function
where
x is the number of U.S. dollars and
is the equivalent number of Euros. Since conversion rates fluctuate, when the tourist returns to the United States 2 weeks later, the conversion from Euros to U.S. dollars is
where
x is the number of Euros and
is the equivalent number of U.S. dollars.
Find the composite function that converts directly from U.S. dollars to U.S. dollars via Euros. Did this tourist lose value in the conversion process?
Use (a) to determine how many U.S. dollars the tourist would get back at the end of her trip if she converted an extra $200 when she arrived in Paris.
[T] The manager at a skateboard shop pays his workers a monthly salary
S of $750 plus a commission of $8.50 for each skateboard they sell.
Write a function
that models a worker’s monthly salary based on the number of skateboards
x he or she sells.
Find the approximate monthly salary when a worker sells 25, 40, or 55 skateboards.
Use the INTERSECT feature on a graphing calculator to determine the number of skateboards that must be sold for a worker to earn a monthly income of $1400. (
Hint : Find the intersection of the function and the line