**How To Determine Increasing And Decreasing Intervals On A Graph Ideas**. You can find the intervals of a function in two ways: Graph the function (i used the graphing calculator at desmos.com).

The function is increasing where it slants upward as we move to the right and decreasing where it slants downward as we move to the right. \displaystyle t=1 t = 1 to. Rules to check increasing and decreasing functions.