2010-03-12, 04:37 PM
Lucida Wrote:Let me rewrite it.
x = 1 + 2 + 4 + 8 + 16 + 32 + ...
2x = 2 + 4 + 8 + 16 + 32 + 64 + ...
x = 1 + (2 + 4 + 8 + 16 + 32 + 64 + ...) = 1 + 2x
x - 1 = 2x To get to the next line you'd have to subtract x on both sides. So you'd get 2x -x which you reduced to x. This does not work when x is something infinitely large. Infinity minus Infinity is undefined, thus the contradiction later.
-1 = x
1 + 4 + 8 + 16 + 32 + ... = -1?
But yes, you're right; the proof is fallacious because divergent series can't be algebraically manipulated like that.

