Regarding the statement
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It is possible to divide by zero. Any non-zero number divided by zero is infinity.
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Interesting Ian said:
It does not seem to be incorrect to me, but I shall avoid making definitive statements since Beth says she agrees with everything you say and I respect her judgement somewhat more than your facile proclamations
Well, you
could actually think about what I write instead of dismissing them as 'facile proclamations.' Although I admit they are facile, since they're extremely easy both to make and to demonstrate.
To start out with,
infinity is not a number. It's a concept, rather like 'truth' or 'justice' or 'love.' So the easy, simple, facile answer of why you can't divide by zero is because there is no 'number' to produce as an answer. A proper handling of infinite quantities requires a limit process.
Another problem is that, as stated, it's incorrect even if treated as a limit process. The limit of any
positive non-zero number, when divided by increasingly smaller quantities, of course increases without bound. But the limit of any
negative non-zero number decreases without bound, which you would naively express as "negative infinity."
But the real problem is simply that division by zero doesn't make sense. There's
a good Dr. Math column on this, which says, among other things
When you divide a number by another number, you can think of splitting it up into groups.
For example, 10/5 (ten divided by five): take the ten and divide it up between five groups so there is nothing left of the ten. You get two in each group, so 10/5 = 2.
This works for numbers that don't divide evenly also: 5/2: take the five and divide it up between two groups so there is nothing left. You can put two in one group and two in the second group, but that leaves a remainder of one. So you can split the one between the two groups and get 2.5 (2 and 1/2) in each group. So 5/2 = 2.5.
However, if you try to do this with zero, it doesn't work. Take any number -- we'll use 10 to make it simple. What happens when you try to split ten up into zero groups with no remainder?? You can't do it! If there aren't any groups, then you can't put the ten anywhere.
Basically, the division concept doesn't make sense when the divisor is zero.
Another way of looking at is is that division is
defined as the inverse of multiplication. So an expression like x/y = z is really the same as y + z = x. But if y is zero, then we have the equivalent expression
0 * z = x (for non-zero x)
You would claim that putting the pseudo-number "infinity" in for z makes the equation true. Unfortunately, multiplication of zero by infinity doesn't make sense --- and even if it did, it would have to have several different values at once, which breaks the rules of multiplication, since it would have to be true simultaneously for every non-zero x there is.
So the facile answer is "it's wrong."
The long, but still facile, answer is "it's wrong because....." As you could have found out for yourself in ten minutes with Google-fu.
Wow, just really wish I was a student in one of your classes. I'd really love to take the p*ss out of you.
You'd last about one term.