Use the given graph of the function $f$ to answer the following questions. If a question has two or more answers separate them with commas.

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1. On what open interval or union of open intervals is $f$ is concave upward? For credit your interval(s) must be as large as possible.
Answer (in interval notation):

2. On what open interval or union of open intervals is $f$ is concave downward? For credit your interval(s) must be as large as possible.
Answer (in interval notation):

3. List the points of inflection. List your answers as points in the form $(a,b)$.
Answer (separate by commas):

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Note: You can click on the graph to enlarge the image.