1/0 is not undefined

No.12245122 ViewReplyOriginalReport
I am absolutely certain 1/0 is not undefined.

Assuming
1/0 is undefined.
0/0 is indeterminate.
(x*y)/z = (x/z)*y

(0*1)/0 = 0/0. 0/0 is indeterminate
(1/0)*0 is undefined, as multiplying an undefined number by 0 is still undefined.
Therefore, 0/0 is both undefined and indeterminate, which is a contradiction.


How can something both be undefined and indeterminate?