options: Define, evaluate, and compare functions.

Use functions to model relationships between quantities.

Model periodic phenomena with trigonometric functions.

Understand the concept of a function and use function notation.

Build new functions from existing functions.

Analyze functions using different representations.

Prove and apply trigonometric identities.

Extend the domain of trigonometric functions using the unit circle.

Interpret expressions for functions in terms of the situation they model.

Construct and compare linear and exponential models and solve problems.

Build a function that models a relationship between two quantities.

Interpret functions that arise in applications in terms of the context.
problem_activity: Task
Katy is told that the cost of producing $x$ DVDs is given by $C(x) = 1.25x + 2500.$ She is then asked to find an equation for $\frac{C(x)}{x}$, the average cost per DVD of producing $x$ DVDs.
She begins her work: $$\frac{C(x)}{x} =\frac {1.25x+2500}{x}$$ and finishes by simplifying both sides to get: $$C = 1.25+\frac{2500}{x}$$  Is Katy's answer correct? Explain.


correct_option_index: 3