"Below is an ”oracle” function. An oracle function is

a function presented interactively. When you type in an x value,

and press the –f–> button and the value f (x) appears in the right

hand window."

Do you not understand what this says? On the webpageyouare working on, by typing a value of x into the blank and pressing the "f->" buttonyousee the value f(x). Since the copy you made does not have that button, no one here can see what values you are working with. To find the limit as x goes to .6666 (2/3),youwill have to put in values of f very close to .6666 and see what value you get.