# and what about 1*0=0 and 1/0=undefined?

Discussion in 'Off-Topic' started by laughing_gas, Apr 27, 2009.

1. ### laughing_gas Thread Starter New Member

Apr 25, 2009
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why is 1 multiplied to zero equals 0? and why is 1 divided by 0 equals zero?

let's say I have 1 apple then I increased it with nothing, won't it give me still an apple? and what if I divide or separate it with nothing, does that not give me 1 apple still?

2. ### vvkannan Active Member

Aug 9, 2008
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If you have one apple and then increase it by 0 is it not 1+0 ?
and hence it is 1.

if you have 1 apple you can divide it among say 2 people but how can you divide it among 0 people?

3. ### laughing_gas Thread Starter New Member

Apr 25, 2009
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i mean multiply..

divide/separate the APPLE by nothing?..

4. ### thingmaker3 Retired Moderator

May 16, 2005
5,072
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To multiply a thing by zero is not to "increase" it, but to specify the quantity. Specified quantity is zero.

Example: I have no luxury cars. There are four tires on each luxury car. How many luxury car tires to I have? Zero!

Division by zero is, of course, an insult in the eyes of the Divine, and you will be punished for all eternity for bringing it up.

5. ### Wendy Moderator

Mar 24, 2008
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A greater or lesser infinity, er, eternity.

6. ### davebee Well-Known Member

Oct 22, 2008
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It seems to me that when you add two numbers, the numbers have the exact same roles in that they both represent some quantity of things.

But when you multiply or divide two numbers, this is not the case. In multiplication or division, one of the numbers represents a quantity of things, but the other does not - it is acting like a sort of command or instruction for what to do with the things.

It's like there are different classes of numbers, and zero does not exist in the class that are used to divide things, so it's not correct to treat the classes of numbers identically, even though they are usually treated as identical things. A number in the numerator of a fraction is a different thing than a number in the denominator.

But I've never heard this concept discussed at any length in any math class. All I've ever heard is the phrase "division by zero is not defined" with an example showing that division by zero leads to math problems. I've never heard any discussion of the
idea that even though non-zero numbers in the denominator work mathematically, numbers in the denominator are a different class of things from the numbers in the numerator.

7. ### studiot AAC Fanatic!

Nov 9, 2007
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Cantor was the guy who first realized that there are different infinities and investigated them. L'Hopital was another.

That is how you can get sense out of fractions such as 0/0 and ∞/∞.

8. ### thingmaker3 Retired Moderator

May 16, 2005
5,072
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Didn't Cantor end up in the looney-bin?

9. ### steveb Senior Member

Jul 3, 2008
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I've heard that a recent ruling in the divine-court has increased the sentence by redefining eternity from cardinality of the natural numbers to that of the real numbers. It is thought that the extra time can be devoted to proving the continuum hypothesis which states that there exists no cardinality between that of the real numbers and the natural numbers.

10. ### studiot AAC Fanatic!

Nov 9, 2007
5,005
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Steve and Thingy3
Is carnality a suitable subject for consideration by the Divine Court or La Divina Comedia?