On what interval is f decreasing

To find the an increasing or decreasing interval, we need to find out if the first derivative is positive or negative on the given interval. So, find . The intervals where a function is increasing (or decreasing) correspond to the intervals where its derivative is positive (or negative).Increasing Function. It is easy to see that y=f(x) tends to go up as it goes along. This function is increasing for the interval shownHow 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. Increasing and Decreasing Intervals Definition · For a real-valued function f(x), the interval I is said to be an increasing interval if for every x < y, we have.