The derivative of a function may be used to determine whether the function is increasing or decreasing on any intervals in its domain. If f′(x) > 0 at each point in an interval I, then the function is said to be increasing on I. f′(x) < 0 at each point in an interval I, then the function is said to be decreasing on I.
How do you find if function is increasing or decreasing?
How can we tell if a function is increasing or decreasing?
- If f′(x)>0 on an open interval, then f is increasing on the interval.
- If f′(x)<0 on an open interval, then f is decreasing on the interval.
How do you find where a function is increasing?
To find when a function is increasing, you must first take the derivative, then set it equal to 0, and then find between which zero values the function is positive. Now test values on all sides of these to find when the function is positive, and therefore increasing.
