What is the result of raising 0.9i to the second power?

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Discussion Overview

The discussion revolves around the mathematical implications of raising the expression 0.9i to the second power, particularly in the context of recurring decimals and their equivalence to whole numbers. Participants explore the nature of imaginary numbers and challenge the definitions and assumptions underlying these mathematical concepts.

Discussion Character

  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant suggests that 0.9i^2 should be calculable and questions if it equals 0.9i, proposing a potential flaw in number theory if they are not equal.
  • Another participant asserts that 0.999... equals 1, leading to the conclusion that (0.999...)^2 also equals 1.
  • A participant questions the equivalence of (0.3...)^2 and 0.9..., suggesting that (0.3...)^2 equals 0.1 instead.
  • Some participants emphasize that the equality of 0.999... and 1 is a mathematical fact based on the definitions of the terms involved, arguing that any alternative system must be explicitly defined.
  • One participant claims that 0.9...i equals 1 and argues that there is no mathematical difference between 0.9i and 1, framing the discussion as an exploration of potential flaws in number theory.
  • Another participant expresses skepticism about the use of "i" to denote infinitely recurring decimals, suggesting it may be a misunderstanding or a joke.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the equivalence of 0.999... and 1, as well as the implications of raising 0.9i to the second power. The discussion remains unresolved, with no consensus on the interpretations or definitions being debated.

Contextual Notes

Participants rely on different interpretations of mathematical terms and concepts, leading to varying conclusions. The discussion highlights the dependence on definitions and the assumptions underlying the mathematical framework being used.

Gamish
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.9i^2 means the square of .9999999999999999999999999999 INFINITE!

.3i^2 = .9i, so .9i should be able to be calculated too.

This is rather an imaginary number, but it should be able to be calculated. If you don't know the exact answer, just tell me if .9i^2 is not .9i

If .9i^2 is something other than .9i, then I think I have found a flaw in number theory, which I will post later. And don't say that .9i^2 = 1, that is another topic :rolleyes:

Thanks in advance
 
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I assume that 'i' is NOT meant to mean sqrt(-1).

0.999... = 1 therefore (0.9999...)^2 = 1^2 = 1
 
How is [itex](.\overline{3})^2 = .\overline{9}[/itex]?

[itex](.\overline{3})^2 = .\overline{1}[/itex], no?

--J
 
that is another topic

Not really -- they both boil down to the meaning of the terms involved. It's a mathematical fact that, in the decimals, [itex]0.\bar{9}=1[/itex]. If you prefer working with a system where that is not true, then you're going to have to explicitly specify how that system works.
 
0.9...i=1

Hurkyl said:
Not really -- they both boil down to the meaning of the terms involved. It's a mathematical fact that, in the decimals, [itex]0.\bar{9}=1[/itex]. If you prefer working with a system where that is not true, then you're going to have to explicitly specify how that system works.

Yes, .9i = 1, I have though this out much, there is mathamaticly no difference from .9i and =, thus, they are equal. My point in creating this new thread was to try to find a flaw in number theory. See, if .9i^2 does not equal (! or <>) 1, then math is flawed, because these 2 problems won't have the same answer.

1. ((1/3)*3)^2
2. 1^2

So, .9...i=.9...i=1?
 
Are we really going to have another 0.9recurring isn't one discussion? By definitoin of the terms involved they are equal, that is the system we have chosen to work in. This isn't a number theoretical fact, it is an analytic choice, one made so that we have a system in which we can do analysis.

As you're not giving a new definition for the symbols, nor are you defining a new algebraic structure, then we msut assume you're using the accepted mathematical ones.

Maths isn't flawed (well, not because of this argument, anyway).
 
The only thing "new" is that unfortunate notion "i" for "infinitely recurring" which then allows him to write "i^2" as if it meant something!

The fact that he then says "This is rather an imaginary number" makes me wonder if this isn't someone's idea of a joke.
 

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