
SECTION
3.1

Functions


SECTION
3.1

EXERCISES 
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Find

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Find

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Find

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Find

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101. 
Budget: Event Planning.
The cost associated with a catered wedding reception is

102. 
Budget: LongDistance Calling.
The cost of a local home phone plan is

103. 
Temperature.
The average temperature in Tampa, Florida, in the springtime is given by the function

104. 
Falling Objects: Firecrackers.
A firecracker is launched straight up, and its height is a function of time,

105. 
Collectibles.
The price of a signed Alex Rodriguez baseball card is a function of how many are for sale. When Rodriguez was traded from the Texas Rangers to the New York Yankees in 2004, the going rate for a signed baseball card on eBay was

106. 
Collectibles.
In Exercise 105, what was the lowest price on eBay, and how many cards were available then? What was the highest price on eBay, and how many cards were available then?

107. 
Volume.
An open box is constructed from a square 10inch piece of cardboard by cutting squares of length

108. 
Volume.
A cylindrical water basin will be built to harvest rainwater. The basin is limited in that the largest radius it can have is
Hint:

109. 
Economics.
Approximate the exchange rates of the U.S. dollar to the nearest yen during Weeks 4, 7, and 8.

110. 
Economics.
Find the increase or decrease in the number of Japanese yen to the U.S. dollar exchange rate, to the nearest yen, from (a) Week 2 to Week 3 and (b) Week 6 to Week 7.

111. 
Medicine/Health.
How many people have contracted malaria 14 days into the outbreak?

112. 
Medicine/Health.
How many people have contracted malaria 6 days into the outbreak?

113. 
Environment: Tossing the Envelopes.
The average American adult receives 24 pieces of mail per week, usually of some combination of ads and envelopes with windows. Suppose each of these adults throws away a dozen envelopes per week.

114. 
Environment: Tossing the Envelopes.
Each month, Jack receives his bank statement in a 9.5 inch by 6 inch envelope. Each month, he throws away the envelope after removing the statement.

115. 
Finance.
Is the relation whose domain is the year and whose range is the average federal funds rate for the month of January a function? Explain.

116. 
Finance.
Write five ordered pairs whose domain is the set of even years from 2000 to 2008 and whose range is the set of corresponding average federal funds rate for the month of January.

117. 
Health Care Costs.
Fill in the following table. Round dollars to the nearest
Write the five ordered pairs resulting from the table.

118. 
Health Care Costs.
Using the table found in Exercise 117, let the years correspond to the domain and the total costs correspond to the range. Is this relation a function? Explain.

119. 
Environment: Global Climate Change.
Estimate (to the nearest thousand) the value of

120. 
Environment: Global Climate Change.
Explain what the sum

121. 
Determine whether the relationship is a function.
Solution:
Apply the horizontal line test.
Because the horizontal line intersects the graph in two places, this is not a function.
This is incorrect. What mistake was made?

122. 
Given the function
Solution:
This is incorrect. What mistake was made?

123. 
Given the function
Solution:
This is incorrect. What mistake was made?

124. 
Determine the domain of the function
Solution:
What can
This is incorrect. What mistake was made?

125. 
Given the function
Solution:

126. 
Given the functions
Solution:
The absolute value of zero is zero, so there is no need for the absolute value signs:
This is incorrect. What mistake was made?

127. 
If a vertical line does not intersect the graph of an equation, then that equation does not represent a function.

128. 
If a horizontal line intersects a graph of an equation more than once, the equation does not represent a function.

129. 
If

130. 
If

134. 
Construct a function that is undefined at

135. 

136. 

137. 
Using a graphing utility, graph the temperature function in Exercise 103. What time of day is it the warmest? What is the temperature? Looking at this function, explain why this model for Tampa, Florida, is valid only from sunrise to sunset (6 to 18).

138. 
Using a graphing utility, graph the height of the firecracker in Exercise 104. How long after liftoff is the firecracker airborne? What is the maximum height that the firecracker attains? Explain why this height model is valid only for the first 8 seconds.

140. 
The makers of malted milk balls are considering increasing the size of the spherical treats. The thin chocolate coating on a malted milk ball can be approximated by the surface area,


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