Based on the summary and the statements provided about the cubic function, let's analyze each statement and confirm the validity of the conclusions drawn:
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Statement: f(x) > 0 over the interval (1, ∞)
- Analysis: This statement is noted as true, meaning the function is above the x-axis for x-values greater than 1.
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Statement: f(x) < 0 over the interval (-∞, -1)
- Analysis: This statement is also marked as true, indicating the function is below the x-axis for x-values less than -1.
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Statement: f(x) > 0 over the interval (-∞, -1)
- Analysis: This statement is false, as it directly contradicts statement 2. The function is not above the x-axis in that interval.
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Statement: f(x) > 0 over the interval (-∞, ∞)
- Analysis: This statement is false. Since the function dips below the x-axis in certain intervals (specifically for the ranges mentioned), it cannot be true that f(x) > 0 for all x-values.
In summary, statements 1 and 2 are supported by the graph, while statements 3 and 4 are clearly incorrect based on the function's behavior described in the graph. The analysis of where the function is positive or negative provides insight into the function's overall shape and can help in applications such as solving inequalities or understanding real-world scenarios modeled by the cubic function.
Understanding the intervals where the function takes positive or negative values can also be crucial for identifying roots, potential maximum and minimum points, and behavior of the function in different contexts, such as in physics or economics where such functions might arise.