MJ: Mathematical Proof: 1 = -1 (Non-bj)

[MJ]

This is fun. Here is a "proof" that 1 = -1.

Let -2 = -2
4 - 6 = 1 - 3
[4 - 6 + (9/4)] = [1 - 3 + (9/4)]
[(2 - (3/2)]^2 = [(1 - (3/2)]^2
2 - (3/2) = 1 - (3/2)
1/2 = -1/2
1 = -1 ???

Please post responses in the message itself and not the subject line. Giving someone the answer before they even read the proof takes away the fun.

MJ

[Don Schlesinger]

> [(2 - (3/2)]^2 = [(1 - (3/2)]^2

This line states that (1/2)^2 = (-1/2)^2, which is certainly true.

But, the next equation takes the square root of both sides, which introduces what is called an "extraneous root."
> 2 - (3/2) = 1 - (3/2)

You can't simply assume that the square roots of both sides of an equation with squared terms are equal. They aren't.

Don