The Power of 0: Is It Just An Agreement?

  • Context: High School 
  • Thread starter Thread starter TSN79
  • Start date Start date
  • Tags Tags
    Power
Click For Summary

Discussion Overview

The discussion revolves around the concept of raising a number to the power of zero, specifically whether the result being equal to one is merely a definition or agreement among mathematicians. Participants explore the implications of this definition and its necessity in maintaining mathematical properties.

Discussion Character

  • Debate/contested
  • Mathematical reasoning
  • Conceptual clarification

Main Points Raised

  • Some participants assert that a number raised to the power of zero equals one is a definition that must be accepted for mathematical consistency, particularly in maintaining the property that x^n * x^m = x^(n+m).
  • Others argue that the definition is not merely arbitrary, emphasizing that it is a necessary convention to avoid contradictions in mathematical operations.
  • A participant suggests that if one were to define a number to the power of zero as zero instead, it would lead to significant changes in mathematical proofs and concepts.
  • Some participants provide examples and reasoning to illustrate why x^0 must equal one, including the manipulation of expressions involving positive integers and the properties of exponents.
  • There is a discussion about the confusion surrounding the implications of 1^0 = 1 and how it relates to other mathematical statements, with some participants drawing parallels to incorrect assumptions.
  • Another participant presents a visual approach to understanding the concept of zero exponents through the process of factoring out a base number.

Areas of Agreement / Disagreement

Participants express differing views on whether the definition of a number raised to the power of zero as one is simply an agreement or a necessary mathematical convention. No consensus is reached, and multiple perspectives remain present.

Contextual Notes

Some participants highlight the importance of definitions in mathematics, while others question the implications of changing those definitions. There are unresolved points regarding the nature of mathematical definitions and their foundational role in proofs.

TSN79
Messages
422
Reaction score
0
We all know that a number to the power of 0 equals 1. Bit I heard this is only a definition, iow something that has just been agreed on. But how can such a thing be done? If one had agreed that it would equal 0 instead, I suppose many mathematical proofs and stuff would be different, things that can't be done suddenly would be possible. Is it really the case that this is just an agreement?
 
Mathematics news on Phys.org
TSN79 said:
We all know that a number to the power of 0 equals 1. Bit I heard this is only a definition, iow something that has just been agreed on. But how can such a thing be done? If one had agreed that it would equal 0 instead, I suppose many mathematical proofs and stuff would be different, things that can't be done suddenly would be possible. Is it really the case that this is just an agreement?
It is according to the definition of raising a number to a power that a nonzero number to the zero power is equal to one, just like it is according to this definition that a x to the second power is x times x. It is really not an unnatural definition. We know that [itex]x^n\times x^m=x^{m+n}[/itex]. If we want this to be true then [itex]x^n\times x^0=x^n \rightarrow x^0=1[/itex]. Alternitively, powers can be defined by series. In this case [itex]b^x=e^{x\ln{b}}[/itex] and
[tex]e^x=1+\sum_{n=1}^{\infty}\frac{x^n}{n!}[/tex]
So
[tex]b^x=e^{0\ln{b}}=1+\sum_{n=1}^{\infty}\frac{0^n}{n!}=1[/tex]
 
Last edited:
TSN79 said:
We all know that a number to the power of 0 equals 1. Bit I heard this is only a definition, iow something that has just been agreed on. But how can such a thing be done? If one had agreed that it would equal 0 instead, I suppose many mathematical proofs and stuff would be different, things that can't be done suddenly would be possible. Is it really the case that this is just an agreement?

Drop the word "just" and I will agree with you. In mathematics, everything in mathematics is a definition but not "just" a definition! As Leonhard Euler said, it is not "an unnatural definition".

From the simplest case, xn with n a positive integer, where we can think of xn as meaning "x multiplied by itself n times" (which is, after all, "just" a definition), we find that xnxm= xn+m because "n times" followed by "m times" is the same as "n+ m times".

If we want that very nice property to continue to be true even if m is 0, we must have xnx0= xn+ 0. But n+0= 0 so we have xnx0= xn. As long as x is not 0, we can divide both sides by xn and get x0= 1.

That is why we define x0 to be 1 (and only define it for x not equal to 0).
 
HallsofIvy said:
Drop the word "just" and I will agree with you. In mathematics, everything in mathematics is a definition but not "just" a definition! As Leonhard Euler said, it is not "an unnatural definition".
From the simplest case, xn with n a positive integer, where we can think of xn as meaning "x multiplied by itself n times" (which is, after all, "just" a definition), we find that xnxm= xn+m because "n times" followed by "m times" is the same as "n+ m times".
If we want that very nice property to continue to be true even if m is 0, we must have xnx0= xn+ 0. But n+0= 0 so we have xnx0= xn. As long as x is not 0, we can divide both sides by xn and get x0= 1.
That is why we define x0 to be 1 (and only define it for x not equal to 0).
Excellent explanation thank you. However N+0=N not N+0=0.
 
HallsofIvy said:
Drop the word "just" and I will agree with you. In mathematics, everything in mathematics is a definition but not "just" a definition! As Leonhard Euler said, it is not "an unnatural definition".
From the simplest case, xn with n a positive integer, where we can think of xn as meaning "x multiplied by itself n times" (which is, after all, "just" a definition), we find that xnxm= xn+m because "n times" followed by "m times" is the same as "n+ m times".
If we want that very nice property to continue to be true even if m is 0, we must have xnx0= xn+ 0. But n+0= 0 so we have xnx0= xn. As long as x is not 0, we can divide both sides by xn and get x0= 1.
That is why we define x0 to be 1 (and only define it for x not equal to 0).

i was confused if 1^0 = 1 and 1^n = 1 (n= 1,2,3...)
then o = 1,2,3...
 
debeng said:
i was confused if 1^0 = 1 and 1^n = 1 (n= 1,2,3...)
then o = 1,2,3...
That's like saying 0*0 = 0 and 0*n = 0 (n= 1,2,3...) then 0 = 1,2,3...

Think about why that isn't true for a moment.
 
This is the example I usually think of when this comes up: 1=xn/xn=xn-n=x0.
 
StatusX said:
This is the example I usually think of when this comes up: 1=xn/xn=xn-n=x0.
That works also.
 
Another way I like to think of it as a notation with xn, where you factor out an x each time n decreases. If x = 3,

x3 = 27

if you factor out three 27/3

x2 = 9

factor out three again 9/3

x1 = 3

and factoring three again 3/3

x0 = 1

I really had trouble visualing "raised to a zero power" and "negative exponents" until I "just" thought of it as a notation.
 

Similar threads

  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 13 ·
Replies
13
Views
3K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 10 ·
Replies
10
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
24
Views
5K
  • · Replies 55 ·
2
Replies
55
Views
7K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 25 ·
Replies
25
Views
8K
  • · Replies 7 ·
Replies
7
Views
3K