ktprktpr! You have revived me, I had a heart attack there.
Please, people, read the post above this. Please.
IR: Sorry.

Without calculus, we would honestly never move because of what I mentioned earlier, Xeno's Paradox. You
need to have infinite
sums converge, and they do. You're right about most functions, however. Most functions aren't even solvable with current methods, and many just
can't be described.
I_S_I_S: We invented square roots for irrationals? We invented square roots because they're the opposite of squaring. sqrt(2) is irrational, yes,
because of the number 2 and the nature of the square root function. Oh well, sucks. Thank god for rounding.
And, uh, .9 can be expressed as a fraction. Easily. 9/10.