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9. Let f (x) = x4 - 2x3 + 1 a. Identify all critical numbers, intervals of increase or decrease, and local extrema of f (x). Critical Numbers Increasing (Interval) Decreasing (Interval) Local Min. Local Max. b. Identify all intervals of concavity and inflection points of f (x). Inflection Pts Concave Up Concave Down c. Sketch a graph of the function