Quote:
Originally Posted by debussybunny563
That's one of the algebraic methods mathematicians use to prove it.
There's also the idea that 0.9 repeating gets closer and closer to 1, but never quite reaches it.

if it's a limit, you use the derivative of whatever function you are using and figure out the number in which this case, if it is .999.... then you could say the limit is (infinty,1)u(1,infinity). and to find the function you started out with you would have to do the antiderivative of .999 which would go to .999x. so like i said before, all depends on the application of the number