Activity
A function , defined by , describes the revenue collected from the sales of tickets for Performance A, a musical.
The graph represents a function that models the revenue collected from the sales of tickets for Performance B, a Shakespearean comedy.
In both functions, represents the price of one ticket, and both revenues and prices are measured in dollars.
Without creating a graph of , determine which performance gives the greater maximum revenue when tickets are dollars each. Explain or show your reasoning.
Compare your answer:
Performance A.
- The maximum revenue for Performance B is $900 based on the vertex (of a graph) of its graph. For Performance A, the expression is in factored form, which tells us that the horizontal intercepts are and . The horizontal coordinate of the vertex is halfway between 0 and 8, which is 4. Substituting 4 for in gives 1200, so the vertex is at . 1200 is greater than 900.
- The maximum revenue for Performance B is $900 based on the vertex of its graph. The expression can be rewritten in vertex form (of a quadratic expression): , which tells us that the vertex of a graph of the function is at and that the maximum revenue is $1200.
Video: Comparing Maximums between Quadratics
Watch the following video to learn more about comparing maximums between quadratics.
Self Check
A function, defined by , describes the revenue collected from the sales of tickets for a concert where is the price of one ticket. Find the maximum revenue, in dollars.
Additional Resources
Finding Maximum Revenue
The revenue brought in by a newspaper is modeled by . Find the maximum revenue where is revenue and is price per newspaper subscription.
Step 1 - Find the horizontal intercepts or -intercepts (where ).
First intercept -
This occurs at or .
Second intercept -
Step 2 - Find the -coordinate of the vertex halfway through the horizontal intercepts.
The vertex (of a graph) will occur halfway between and . This occurs when .
Step 3 - Write in the function in standard form and substitute .
The maximum revenue is at $2,528,100 with a $31.80 subscription.
Try it
Try It: Finding Maximum Revenue
Suppose that the price per unit in dollars of a cell phone production is modeled by , where is in thousands of phones produced, and the revenue represented by thousands of dollars is . Find the production level that will maximize revenue and the maximum revenue.
Here is how to find the maximum revenue:
Step 1 - Find the horizontal intercepts.
and
Step 2 - Find the -coordinate of the vertex halfway through the horizontal intercepts.
This is the number of phones produced for the maximum revenue.
Step 3 - Find the equation for and substitute to find the maximum revenue.