Proving a^0=1: Step-by-Step Guide

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Discussion Overview

The discussion revolves around the proof of the expression \( a^0 = 1 \) for non-zero \( a \). Participants explore various definitions, motivations, and implications of this expression, including its mathematical foundations and the continuity of exponential functions. The scope includes theoretical reasoning, definitions, and some mathematical exploration.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant proposes a proof based on the definition of \( a^n \) and \( a^m \) for positive integers, suggesting that if \( m = 0 \), then \( a^0 = 1 \).
  • Another participant challenges the validity of the proof, stating it only holds for positive integers and questions whether it can be considered a proof at all.
  • Some participants assert that \( a^0 = 1 \) is a definition chosen to maintain the property \( a^n a^m = a^{n+m} \), implying that it is not derived from a proof but rather a necessary definition.
  • There is a suggestion that defining \( a^0 \) as 1 is similar to defining \( 0! = 1 \), indicating a motivational rather than a proof-based approach.
  • One participant introduces the idea of continuity in the function \( f(x) = a^x \) and suggests showing that certain sequences converge to 1 as a way to justify \( a^0 = 1 \).
  • Another participant discusses the implications of defining \( a^0 \) in various mathematical contexts, such as groups and semigroups, highlighting that definitions may vary based on the structure being considered.
  • There is a mention of the associative law of multiplication and how it relates to the expression \( a^0 \), with some arguing that the definition of \( a^0 \) is necessary for the law to hold for all integers.
  • One participant presents a sequence to illustrate the necessity of defining \( 2^0 = 1 \) to maintain consistency in the pattern of powers.

Areas of Agreement / Disagreement

Participants express differing views on whether \( a^0 = 1 \) can be proven or if it should be accepted as a definition. Some agree that it is a necessary definition for consistency in mathematical operations, while others argue that it lacks a rigorous proof. The discussion remains unresolved with multiple competing views on the nature of the proof and definition.

Contextual Notes

Participants note that the proof of \( a^0 = 1 \) may depend on the definitions and properties assumed for exponentiation, particularly when extending the concept to non-positive integers. There is also mention of the limitations of defining exponentiation in various mathematical contexts, which may affect the interpretation of \( a^0 \).

  • #91
I always thought that a point is nil-dimensional.

Perhaps I didn't convey the meaning properly that a power is dimensionality... ( i hope you don't take all this so seriously, eh? )
 
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  • #92
PeroK said:
If we have a cube of side 2, it's volume is 8, Or, if we have a cube of bricks, with each side 2 bricks long, we have 8 bricks.

For a square of side 2, it's area is 4. Or, a square of bricks needs 4 bricks.

For a line of length 2, it's length is 2. Or, a line of bricks needs 2 bricks.

For a point, it's size is 0. Or, if we have a zero-dimensional array of bricks, then there are no bricks.

By this intuitive reasoning, we should have ##2^0 = 0##.

Very, very wrong.

2^4 is the Figurate Number represented by the vertices (points) of a hypercube ( Dimension 4 }

2^3 is the Figurate Number represented by the vertices (points) of a cube ( Dimension 3 )

2^2 ................ of a square.

2^1 ........... by the end points of a line. ( Dimension 1 )

And 2^0 is just the point or the atom itself of Nil-Dimension.
 
  • #93
rada you are quite right that we need the condition f(0) ≠ 0, and this is guaranteed by my assumption that f(x+y) = f(x).f(y) for all x,y, and f(n) = a^n for n = a positive integer and a > 0, since then f(1) = a ≠ 0, and thus f(x) ≠ 0 for all x. (if f(x) = 0, for some x, then for all y, f(y-x + x) = f(y-x).f(x) = f(y-x).0 = 0. i.e. thus either f(x) = 0 for all x or f(x) never equals zero.)
 

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