107. Marginal cost The accompanying graph shows the hypothetical cost c=f(x) of manufacturing x items. At approximately what production level does the marginal cost change from decreasing to increasing?
Table of contents
- 0. Functions7h 52m
- Introduction to Functions16m
- Piecewise Functions10m
- Properties of Functions9m
- Common Functions1h 8m
- Transformations5m
- Combining Functions27m
- Exponent rules32m
- Exponential Functions28m
- Logarithmic Functions24m
- Properties of Logarithms34m
- Exponential & Logarithmic Equations35m
- Introduction to Trigonometric Functions38m
- Graphs of Trigonometric Functions44m
- Trigonometric Identities47m
- Inverse Trigonometric Functions48m
- 1. Limits and Continuity2h 2m
- 2. Intro to Derivatives1h 33m
- 3. Techniques of Differentiation3h 18m
- 4. Applications of Derivatives2h 38m
- 5. Graphical Applications of Derivatives6h 2m
- 6. Derivatives of Inverse, Exponential, & Logarithmic Functions2h 37m
- 7. Antiderivatives & Indefinite Integrals1h 26m
- 8. Definite Integrals4h 44m
- 9. Graphical Applications of Integrals2h 27m
- 10. Physics Applications of Integrals 3h 16m
- 11. Integrals of Inverse, Exponential, & Logarithmic Functions2h 34m
- 12. Techniques of Integration7h 39m
- 13. Intro to Differential Equations2h 55m
- 14. Sequences & Series5h 36m
- 15. Power Series2h 19m
- 16. Parametric Equations & Polar Coordinates7h 58m
5. Graphical Applications of Derivatives
Concavity
Struggling with Calculus?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
Suppose the graph of is shown above. Which of the following best describes the graph of ?
A
It is zero wherever the graph of has a local maximum or minimum.
B
It is positive where the graph of is increasing and negative where is decreasing.
C
It is always positive if is above the -axis.
D
It is positive where the graph of is concave up and negative where is concave down.

1
Step 1: Understand the relationship between the function y = f(x), its first derivative y = f'(x), and its second derivative y = f''(x). The second derivative provides information about the concavity of the graph of y = f(x).
Step 2: Recall that concavity describes how the graph curves. If y = f''(x) > 0, the graph of y = f(x) is concave up (curving upwards like a U). If y = f''(x) < 0, the graph of y = f(x) is concave down (curving downwards like an upside-down U).
Step 3: Identify the points of inflection on the graph of y = f(x). These are the points where the concavity changes, and y = f''(x) is zero at these points.
Step 4: Analyze the behavior of y = f(x) in regions where it is concave up or concave down. In regions where y = f(x) is concave up, y = f''(x) will be positive. In regions where y = f(x) is concave down, y = f''(x) will be negative.
Step 5: Conclude that the correct description of the graph of y = f''(x) is: 'It is positive where the graph of y = f(x) is concave up and negative where y = f(x) is concave down.' This aligns with the properties of the second derivative.
Watch next
Master Determining Concavity from the Graph of f with a bite sized video explanation from Patrick
Start learningRelated Videos
Related Practice
Textbook Question
35
views