>>12
No, division by zero is simply -forbidden-, not "undefined".
Because you don't know what you get.
The reason is that rearranging 1/0 = whatever to 1 = whatever * 0 can't be fulfilled unless it is taken as an axiom which leads to the principle of explosion (see wikipedia). You implicitly assumed a contradiction making anything provable.
Or in school logic: since 1/0 gives "infinity" we now can't guarantee that * 0 will cancel it out. You would never be done with the prove which would go like 0*infinity = 0*(1+2+3+4+5+6...forever) = 0*1 + 0*2 + 0*3 + ... + zero*forever+zero*forever+1....