AP Calculus BC · Unit 5: Analytical Applications of Differentiation

5.3 Determining Intervals on Which a Function Is Increasing or Decreasing

In short

This topic focuses on using the first derivative to analytically determine intervals where a function is increasing or decreasing. The superficial details of contextual applications are stripped away to focus on abstract structures and formal conclusions. You must transition from conjectures based on graphs to calculus-based justifications (i.e., reasoning based on the analysis of a derivative).

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Can you do these?

  • I can use the first derivative of a function to determine intervals where the function is increasing or decreasing.

How is Determining Intervals on Which a Function Is Increasing or Decreasing tested on the exam?

On the AP Exam, sound reasoning must be accompanied by clear communication. Many students struggle by misinterpreting the characteristics of the graph of a derivative as though they are characteristics of the original function. You also tend to rely on insufficient evidence (e.g., stating 'the graph of f is increasing because it's going up'). You are expected to refer to functions by their specific names (e.g., f, f', f'') rather than using nonspecific pronouns like 'it' or 'the function', which can result in a loss of points. Justifications must be calculus-based.

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Determining Intervals on Which a Function Is Increasing or Decreasing: common questions

What do you need to know about Determining Intervals on Which a Function Is Increasing or Decreasing for AP Calculus BC?

This topic focuses on using the first derivative to analytically determine intervals where a function is increasing or decreasing. The superficial details of contextual applications are stripped away to focus on abstract structures and formal conclusions. You must transition from conjectures based on graphs to calculus-based justifications (i.e., reasoning based on the analysis of a derivative).

How is Determining Intervals on Which a Function Is Increasing or Decreasing tested on the AP Calculus BC exam?

On the AP Exam, sound reasoning must be accompanied by clear communication. Many students struggle by misinterpreting the characteristics of the graph of a derivative as though they are characteristics of the original function.

How do I know I have mastered Determining Intervals on Which a Function Is Increasing or Decreasing?

Check you can do each of these: use the first derivative of a function to determine intervals where the function is increasing or decreasing.

Where does Determining Intervals on Which a Function Is Increasing or Decreasing fit in AP Calculus BC?

Determining Intervals on Which a Function Is Increasing or Decreasing is topic 5.3 in Unit 5: Analytical Applications of Differentiation of AP Calculus BC.

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