The range of a function f(x) is the set of all the values that f takes, or the values of y.
A function increase in an interval if f(b) ≥ f(a), when b> a.
A function decrease in an interval if f(b) ≤ f(a), when b>a.
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In the given function you have:
Increasing: The grpah increase in the interval (-∞ ; 1)
Decreasing: The grpah decrease in the interval ( 1 , ∞ )
Range: As there is not an endpoint in the graph the range is: (-∞ , 2]
