so you multiply by 3 over 3 and the equation becomes
and then it cancels and you get
and the answer is 0?
yes, the answer is zero, but i do not like how you phrased it. what do you mean "cancels"? we didn't cancel anything here. and where is your limit? you have to take the limit to see what happens. you can't just equate things like that and say this is equal to that. it doesn't work