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Old 10-15-2005, 01:26 PM
BruceZ BruceZ is offline
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Join Date: Sep 2002
Posts: 1,636
Default Re: Ok so I just proved 1 = -1. Someone help me find my error.

[ QUOTE ]
Here's another "proof" in this vein that I've always found enjoyable:

x^2 = x + x + . . . x (x copies of x)

Differentiate both sides:

2x = 1 + 1 + 1 . . . = x

Divide by x:

2 = 1.

[/ QUOTE ]

Good one. The problem here is that

x^2 = x + x + . . . x (x copies of x)

is only true for integer x, and if this function is only defined for integer x, then the function is discreet and is not differentiable.
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