Is it true that 2 = 1?

Question

Let x = y
Multiplying by x,
x^2 = xy
Subtracting y^2,
x^2-y^2 = xy - y
Factoring,
(x-y)(x+y) = (x-y) y
cancelling (x-y) on both sides,
x+y = y
but x = y by assumption, so
y + y = y
2y=y
cancelling y,
2 = 1 Proved.

I wonder why?

Answer 1

Only during sex.

Answer 2

No, this is not true.

The mathematical violation occurred when you canceled the (x-y) on both sides. Since x = y, (x-y) = 0, and dividing by zero is not allowed.

Answer 3

slight misstep in your calculation... its only a small mistake but it is clear that in an equasion like this even the smallest error can lead to a misleading conclusion. 2 does not equal 1 it equals 2... simply put.

Answer 4

No, it's not true because when you were factoring you violated a rule, so 2 doesn't equal 1.

Answer 5

Because when you divided by (x-y) on both sides, you basically divided by 0, because you let x = y.

When you divide by 0, everything becomes screwy... Thus the screwy answer :-)

Answer 6

Like Bill explained, you divided by zero. In mathematics when you divide by zero you get infinity. One infinity equals two infinities.

Answer 7

No, you can't cancel (x-y) on both sides because that would mean that you're dividing by zero.

Answer 8

Because true loves conquers all, and especially when enthralled in the throes of passion.

Answer 9

The cancelling (x-y) step is division by zero, invalidating the "proof".

Answer 10

>> cancelling (x-y) on both sides,

Because x=y, (x-y)=0, hence you have divided by 0.