Yahoo Answers is shutting down on 4 May 2021 (Eastern Time) and the Yahoo Answers website is now in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
How can 1 = 0?
My dad once told me a story of his maths teacher being able to make 1 = 0 by a series of complex but accurate mathematics. Anyone know what it is? Or was his maths teacher on the 1950's equivalent of strange cigarettes?
15 Answers
- Anonymous1 decade agoFavourite answer
Yes, the only way involves dividing by zero. If you're interested, here's how to do it.
Take two numbers a and b and put them equal.
thus a=b
Now multifly each side of the equation by a
a^2=ab
Subtract b^2 from each side
a^2-b^2=ab-b^2
Now factorise
(a+b)(a-b) = b(a-b)
Divide each side by (a-b) {NB (a-b) =0 since a=b so we can't do this!)
a+b = b
Noting that a=b we have
2a=a
which means
2=1
subtracting 1 from each side
1=0
QED (except it isn't because of the illegal step of dividing by zero).
- Jun AgrudaLv 71 decade ago
This could involve an operation. But to say 1 = 0 is false. 1 = 1 and 0 = 0 are true but never is 1 = 0 or 0 = 1.
- Anonymous1 decade ago
I suspect it trickery to do with multiple roots that your father encountered.
e.g. a = sqrt(a) * sqrt(a) , but if you slip in a -ve square root in one of them you get
a = -sqrt(a) * sqrt(a) = -a (a falsehod)
so 2a = a + a = a - a =0
then you can do anything
e.g.
1 = (1+1) / 2
= (1 + (sqrt(1) * sqrt(1)) / 2
= (1 + (1 * -1))/2 (a false step)
= (1 - 1) / 2 = 0
- MontyHLv 51 decade ago
Consider the following problem. Let x=1 and y=1. Then, of course, x=y. Multiplying both sides of the equation by x gives us x2 =xy. Subtracting y2 from both sides makes it x2-y 2 = xy-y2.. If we factor both sides of this equation, we get (x+y)(x-y) = y(x-y). Now, we can divide both sides by (x-y), leaving x+y = y. Substituting the original numbers for x and y produces a simple, yet suspicious result: 2=1.
(X=y=1; then x-y = 0 division by 0 leads to poor result)
- 1 decade ago
To the untrained eye it can be a clever trick, but in reality there's an illegal algebra step, namely, dividing by zero, somewhere in the process of trying to prove 1=0.
A college professor once said you can do lots of stuff if you could divide by zero!
- Anonymous1 decade ago
1 multiplied by 0 = 0 simple wnen you think about it
- Phil McCrackenLv 51 decade ago
This can be proved only by using division by zero, which is, of course, a mathematical anomaly, which is what the teacher was demonstrating.