1. QUADRATIC MODELS: BUILDING QUADRATIC FUNCTIONS
SECTION 2.6
QUADRATIC MODELS: BUILDING QUADRATIC FUNCTIONS

2. MAXIMIZING INCOME
A car rental agency has 24 identical cars. The owner of the agency finds that all the cars can be rented at a price of $10 per day. However, for each $2 increase in rental, one of the cars is not rented. What should be charged to maximize income?

3. DEMAND EQUATION
In economics, revenue R is defined as the amount of money derived from the sale of a product and is equal to the unit selling price p of the product times the number x of units sold.
R = xp

4. DEMAND EQUATION Express the revenue R as a function of x.
In economics, the Law of Demand states that p and x are related: As one increases, the other decreases.
Example: Suppose x and p obeyed the demand equation: x = - 20p where 0 < p < 25.
Express the revenue R as a function of x.

5. DEMAND EQUATION Express the revenue R as a function of x.
x = - 20p where 0 < p < 25.
Express the revenue R as a function of x.
R = xp so in order to write R as a function of x, we have to know what p is in terms of x and then replace p with that expression in R.

6. DEMAND EQUATION R = xp x = - 20p + 500 where 0 < p < 25.
Find the maximum Revenue.

7. EXAMPLES
Beth has 3000 feet of fencing available to enclose a rectangular field.
a. Express the area of the rectangle as a function of x, the length of the rectangle.
b. For what value of x is the area largest?
c. What is the maximum area?

8. EXAMPLES
A farmer with 2000 meters of fencing wants to enclose a rectangular plot that borders on a straight highway. If the farmer does not fence the side along the highway, what is the largest area that can be enclosed?

9. CONCLUSION OF SECTION 2.6