Find the interval in which f (x) = x3 – 3x2 – 9x + 20 is strictly increasing or strictly decreasing.
Strictly increasing and strictly decreasing x Ïµ (–1, 3)
Given f (x) = x3 – 3x2 – 9x + 20
Using number line method, as shown in figure
Thus, f (x) is strictly increasing for and strictly decreasing for x Ïµ (–1, 3).
Local minimum at x = 2, then
a minimum at x= 1 is the value of a is
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The minimum value of
Find the interval in which f (x) = 2x3 + 3x2 – 12x + 1 is increasing.
Find the interval of increase or decrease of the