Proving x*0=0 without m(-1)=-m

  • Thread starter Ed Quanta
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In summary, the conversation discusses how to prove that x*0=0 for any integer x. The use of the proposition m(-1)=-m is not allowed, but it is necessary to accept the fact that anything times zero equals zero to prove it. The hint given is to use the definition of multiplication when a=0.
  • #1
Ed Quanta
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I have to prove that x*0= 0 where x is any integer. I can do this pretty easily using the proposition that m(-1)=-m but I am not allowed to use this. In addition, I am unable to prove m(-1)=-m unless I accept the fact that anything times zero equals zero. Can anyone give me a hint or push on how to show this? I am just going around in circles.
 
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  • #2
0.m=(0+0).m =0.m+0.m

subtract m.0 from both sides.
 
  • #3
Thanks, I am an idiot. I kept trying to represent 0 as (m + -m)
 
  • #4
When x is an integer, multiplication can be defined as:

[tex]x*a = \sum^x_{n=1} a[/tex]

When a = 0:

[tex]x*0 = \sum^x_{n=1} 0 = \underbrace{0 + 0 + ... + 0}_x = 0[/tex]
 
Last edited:

1. How can x*0 equal 0 without using the fact that m(-1)=-m?

There are several ways to prove that x*0=0 without relying on the property m(-1)=-m. One approach is to use the definition of multiplication as repeated addition and show that when x is multiplied by 0, the result is always 0. Another method is to use the distributive property and show that when 0 is multiplied by any number, the result is always 0.

2. Can you provide an example to illustrate x*0=0 without using m(-1)=-m?

Sure, let's take the example of x=5. When 5 is multiplied by 0, we get 5*0=0. This can be shown using the repeated addition method by adding 0 to itself 5 times, or using the distributive property by distributing 0 to each term in the expression 5*0.

3. Is it possible to prove x*0=0 without using any properties or axioms?

No, in order to prove a mathematical statement, we must use some basic properties and axioms. However, it is possible to prove x*0=0 using only fundamental properties such as the definition of multiplication and the commutative and distributive properties.

4. Why is it important to prove x*0=0 without relying on m(-1)=-m?

Proving x*0=0 without using the property m(-1)=-m helps to strengthen our understanding of the fundamental properties of multiplication and the relationships between different numbers. It also allows us to verify that the property m(-1)=-m is not a fundamental axiom, but can be derived from other properties.

5. Can x*0 ever equal a number other than 0?

No, by the definition of multiplication and the properties of 0, the only possible result of multiplying any number by 0 is 0. This can be verified through examples or by using the properties of multiplication and the fact that x*0=0 can be rewritten as x*(0+0)=x*0+x*0, which simplifies to 0=0.

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