Graphs - Increasing/Decreasing Intervals

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SUMMARY

The discussion focuses on determining the intervals of increase for the function f(x) based on its derivative f'(x) and identifying concavity from the graph of f'(x). Participants incorrectly identified the intervals, with one suggesting that f(x) increases over the entire range (-∞, ∞) and another misinterpreting concavity as being represented by the interval (0, ∞). The key takeaway is that f(x) is increasing where f'(x) is positive, and concavity is determined by the sign of the second derivative, f''(x), which is not explicitly provided in the graphs discussed.

PREREQUISITES
  • Understanding of derivatives and their graphical representations
  • Knowledge of the relationship between a function and its first derivative
  • Familiarity with concavity and the second derivative test
  • Basic graph interpretation skills
NEXT STEPS
  • Study the relationship between f(x) and f'(x) in detail
  • Learn about the second derivative test for concavity
  • Practice identifying intervals of increase and decrease using various functions
  • Explore graphical analysis techniques for interpreting function behavior
USEFUL FOR

Students studying calculus, particularly those learning about derivatives, concavity, and graph analysis. This discussion is beneficial for anyone seeking to improve their understanding of function behavior through graphical interpretation.

ceity
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Homework Statement


#1: The graph of f' is shown. Find the intervals on which f increases.

#2: The graph of f'(x) is shown. Give the interval(s) where the graph in concave down.


Homework Equations


Not sure.


The Attempt at a Solution


#1: Well, I thought it was (-infinity, infinity), but I got incorrect. X and Y are both increasing.

#2: I got (0, infinity) incorrect, which confuses me, because I thought concave down was like an upside down U.
 

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ceity said:

Homework Statement


#1: The graph of f' is shown. Find the intervals on which f increases.

#2: The graph of f'(x) is shown. Give the interval(s) where the graph in concave down.


Homework Equations


Not sure.


The Attempt at a Solution


#1: Well, I thought it was (-infinity, infinity), but I got incorrect. X and Y are both increasing.

#2: I got (0, infinity) incorrect, which confuses me, because I thought concave down was like an upside down U.

The problem says those are the graphs of f'(x) and then the first questions asks about where f(x) is increasing, not f'(x). How can you tell if f(x) is increasing from knowing f'(x)? It's likely the second one means the same though they don't spell out which graph is supposed to be concave. It also might be a stretch claiming you know what the graph looks like near infinity when they are only showing you a small part.
 

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