Math Problem Statement

Copy the graph of each function given. On the same set of axes, sketch the graphs of the first and second derivatives of the function.

Solution

To analyze this problem, let's interpret the graph provided and understand how we can sketch the first and second derivatives based on the behavior of the original function f(x)f(x):

Analyzing the Original Function f(x)f(x)

  1. Critical Points (where the slope is zero):

    • Around x=2x = 2: The function reaches a local maximum.
    • Around x=5x = 5: The function reaches a local minimum.
    • These points will be where the first derivative f(x)=0f'(x) = 0, as the slope is zero at maxima and minima.
  2. Intervals of Increase and Decrease:

    • From x=0x = 0 to x2x \approx 2: The function increases, so f(x)>0f'(x) > 0.
    • From x2x \approx 2 to x5x \approx 5: The function decreases, so f(x)<0f'(x) < 0.
    • From x5x \approx 5 to x7x \approx 7: The function increases again, so f(x)>0f'(x) > 0.
  3. Concavity (for the second derivative):

    • Between x=0x = 0 and x3x \approx 3: The graph is concave down, so f(x)<0f''(x) < 0.
    • Between x3x \approx 3 and x6x \approx 6: The graph is concave up, so f(x)>0f''(x) > 0.
    • Around x3x \approx 3 and x6x \approx 6: These points appear to be inflection points where concavity changes, so f(x)=0f''(x) = 0.

Sketching the Derivatives

  1. First Derivative f(x)f'(x):

    • Starts positive, reaches zero at x2x \approx 2 (maximum of f(x)f(x)), turns negative, and then zero again at x5x \approx 5 (minimum of f(x)f(x)).
    • The graph of f(x)f'(x) would cross the x-axis at x=2x = 2 and x=5x = 5.
    • Between these values, f(x)f'(x) is negative, and outside of them, it is positive.
  2. Second Derivative f(x)f''(x):

    • The second derivative f(x)f''(x) indicates the concavity of f(x)f(x).
    • It is negative from x=0x = 0 to x3x \approx 3 (concave down), zero at x3x \approx 3 (inflection point), positive from x3x \approx 3 to x6x \approx 6 (concave up), and zero again at x6x \approx 6 (another inflection point).

Would you like a more detailed explanation on how to construct these derivative graphs, or a visualization to aid in understanding?


Follow-Up Questions

  1. What is the significance of critical points in determining the behavior of the first derivative?
  2. How does concavity in f(x)f(x) relate to the behavior of the second derivative?
  3. Can you explain why inflection points are where the second derivative equals zero?
  4. How would the behavior of f(x)f'(x) change if there were additional extrema in f(x)f(x)?
  5. Why is it important to consider both the first and second derivatives when analyzing the shape of a function?

Tip:

When sketching derivatives, always start by identifying maxima, minima, and inflection points in the original function. These points provide valuable anchors for the shapes of the first and second derivatives.

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Math Problem Analysis

Mathematical Concepts

Calculus
Derivatives
Critical Points
Concavity
Inflection Points

Formulas

f'(x) = 0 at critical points (maxima and minima)
f''(x) = 0 at inflection points

Theorems

First Derivative Test
Second Derivative Test

Suitable Grade Level

Grades 11-12