how can i prove that identity...tks
can u explain me what did you do in that step? i didnt get that one...
I needed the middle term so that I could factor the ... to compensate adding it, I also had to also subtract it, resulting in the term.
why didnt you use
why do that? it won't factor.
i know that we want that 3 but can we add terms just like that?
sure can ... isn't ?