Proof That 2 Does Equal 1!
Date: 03/24/97 at 21:47:56 From: Anonymous Subject: 2 Does Equal 1! Hi I was sitting in English Class, and, Math being my TRUE subject :), I got bored and started thinking of math. I wrote out a little proof that 2 = 1. I know that it's impossible, so I thought that you could show me where the proof goes wrong. Here it is: 1) x = y 2) x^2 = xy (multiply both sides by x) 3) x^2 - y^2 = xy - y^2 (subtract y^2 from each side) 4) (x + y)(x - y) = y(x - y) (factor) 5) x + y = y (divide out (x - y)) 6) 2y = y (substitute y for x from #1) 7) 2 = 1 (What do you think of that?!) Thanks a lot Dr. Math! You're a real inspiration to us resident Dr. Math Hopefuls! -Anoymous
Date: 03/25/97 at 14:38:02 From: Doctor Steven Subject: Re: 2 Does Equal 1! Your mistake comes in step 5, when you divided by (x-y) on both sides. Since x = y, x-y = 0, so you are dividing by zero, which is undefined (illegal!). Besides, if 2 = 1 then I'm the Pope. Proof: 2 = 1. The Pope is one, and I'm one, so the Pope and I are two. From the equation, the Pope and I are one. So I am the Pope. :=) -Doctor Steven and Dr. Chuck, The Math Forum Check out our web site! http://mathforum.org/dr.math/
Search the Dr. Math Library:
Ask Dr. MathTM
© 1994- The Math Forum at NCTM. All rights reserved.