Example 1

The cost of pork chops per kilogram is represented in the two different graphs.

The cost of pork chops is $10.50/kg. Sharon is planning a meal for her extended family of 25. She has determined she will need 4.5 kg of pork chops.

Based on the graphs provided:

  1. Estimate the cost of 4.5 kg of pork chops.

  2. Identify which graph is easier to use when interpolating data.

  3. Is the pork chop data continuous or discrete? Explain.

  4. Why are negative values not included in the graphs?

  5. State the domain and range for the relation.

a. Estimate the cost of 4.5 kg of pork chops.

The pork chops will cost approximately $48.

b. Identify which graph is easier to use when interpolating data.

The connected line graph is easier.

c. Is the pork chop data continuous or discrete? Explain.

The data is continuous because for any mass of pork chops (whole kilograms or decimals), there is a cost that can be determined.

d. Why are negative values not included in the graphs?

For the given context, negative values do not make sense. There is no negative mass of meat and there are no negative costs.

e. State the domain and range for the relation.




Negative values are very much involved in certain contexts and thus many graphs extend beyond Quadrant I. Temperature values collected during the month of January 2013 in Edmonton, Alberta are discussed in Example 2.

Example 2

Use the information provided in the graph to determine:

The domain is restricted to Whole Numbers because there is exactly one temperature value for each day in January. There is no restriction on the range because temperature values are measurements that can take on any value.

Which three consecutive days had the same temperature?

January 16th, 17th, and 18th

Which three day period had the greatest change in temperature?

January 18th, 19th, and 20th

Why is this data discrete and not continuous?

These are the daily averages, of which there can be only one for each day.

State the domain and range for the relation.