Re: [TCLUG:14710] Many topics..

["Thomas.Veldhouse (Exchange)" <Thomas.Veldhouse@target.com>]

> On Wed, 15 Mar 2000 rgoldber@d.umn.edu wrote:
> > a = b
> > a^2 = ab
> > a^2 - b^2 = ab - b^2
> > (a + b)(a - b) = b(a - b)
> > a + b = b
> > 2b = b
> > 2 = 1
> > !
> > Thanks for putting up with my long, largely irrelevant email!!
> 
> divide by zero. only possible explanation. if i get time later, i'll
> figure out where it is.  :)

What is the point of this exercise?  Are you trying to prove a = b?

You really should note that a - b is always is equal to zero.

thus

a = b

a^2 = ab

a^2 - b^2 = ab - b^2

(a + b)(a - b) = b(a - b)

(a + b)(0) = b(0)

a + b    b
----- =  -
  0      0

You can not factor out a 0, as it would be a divide by zero error.  You
prove nothing.

Tom Veldhouse
veldy@visi.com