Is (-1)^x a discontinuous function?

  • Context: Undergrad 
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Discussion Overview

The discussion revolves around the function y=(-1)^x and whether it is discontinuous. Participants explore the implications of raising -1 to various types of numbers, including integers, rationals, and irrationals, and consider the behavior of the function across different values of x.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant suggests that the function is discontinuous because it alternates between positive and negative values depending on whether x is even or odd.
  • Another participant counters that the concepts of even and odd apply only to integers, and therefore the function's behavior for continuous variables like real numbers is more complex.
  • A third participant acknowledges uncertainty about the function's value for non-integer inputs, such as 0.5, suggesting it could be positive, negative, or undefined.
  • There is a challenge regarding the interpretation of raising -1 to a fractional power, specifically questioning the result of (-1)^0.5.

Areas of Agreement / Disagreement

Participants do not reach a consensus; there are multiple competing views regarding the continuity and behavior of the function for different types of numbers.

Contextual Notes

Limitations include the ambiguity of defining the function for non-integer values and the implications of raising negative numbers to fractional powers, which remain unresolved.

cp255
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So I was thinking about the equation y=(-1)x. This equation will jump back and fourth across the x-axis depending on weather x is even or not. This must mean that the function is discontinuous. Figuring out if the value is positive or negative is straight forward for ration numbers but how can we tell if say (-1)^pi is negative or positive since we don't know if pi is even or odd.
 
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It's not that simple. Remember x is a continuous variable, and the quality of even or odd applies only to integers. There are no even or odd rational or irrational numbers.

The equation in the OP is defined for real numbers only when abs(x) > 0. Do you know what y equals when x equals 1/2?
 
Last edited:
I never thought of what it would be be when x=0.5. So I guess it can be positive negative or undefined.
 
Don't you know what it means to raise a number to a power of 0.5? Does square root come to mind?

What is the square root of -1?
 

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