Imaginary numbers negative confusion

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Discussion Overview

The discussion revolves around the confusion regarding the multiplication of negative numbers and the concept of imaginary numbers, particularly in relation to Fermat's Last Theorem. Participants explore the implications of negative multiplication and the necessity of imaginary numbers in mathematics.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant questions why multiplying two negative numbers results in a positive number, expressing confusion over the logic behind this operation.
  • Another participant references Bombelli's introduction of imaginary numbers in relation to Fermat's Last Theorem, suggesting a historical context for understanding these concepts.
  • There is a discussion about the nature of real numbers, where one participant asserts that all real numbers are either positive, negative, or zero, and that imaginary numbers fill a gap in this understanding.
  • Concerns are raised about the interpretation of negative values, with one participant arguing that negative numbers should not be viewed as less than zero but as valid numbers in their own right.
  • A participant discusses the analogy of temperature, arguing that if a temperature drops from -5 to twice as low, it should be -15, reflecting confusion over how negative values operate in mathematical contexts.
  • Another participant suggests that thinking of negative values as opposites may clarify the confusion surrounding operations involving negative numbers.

Areas of Agreement / Disagreement

Participants express differing views on the nature of negative numbers and their operations, with no consensus reached on the underlying principles of multiplication involving negatives or the necessity of imaginary numbers.

Contextual Notes

Some participants reference specific pages in Fermat's Last Theorem and the historical development of imaginary numbers, indicating that the discussion may be influenced by varying interpretations of mathematical concepts and definitions.

Who May Find This Useful

This discussion may be of interest to those exploring foundational concepts in mathematics, particularly students grappling with the implications of negative numbers and imaginary numbers.

genphis
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i know this must seem real stupid but if 1 x 1 =1 ( square root wise) how can -1x-1=+1 again square root wise. i am reading fermats last theorum to me if you times negative you increase the negative. i don't see why the imaginary numbers need to be invoked. i understand the argument for vectoring and working on a plane(number plane) if you are creating virtual dimensions and so on. i know i must have just missed the point please enlighten me
 
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genphis said:
i know this must seem real stupid but if 1 x 1 =1 ( square root wise) how can -1x-1=+1 again square root wise. i am reading fermats last theorum to me if you times negative you increase the negative. i don't see why the imaginary numbers need to be invoked. i understand the argument for vectoring and working on a plane(number plane) if you are creating virtual dimensions and so on. i know i must have just missed the point please enlighten me

What do you mean "1 x 1 =1 ( square root wise)"? What does any of this have to do with imaginary numbers?
 
hi mark44 thanks for your thread,

read page 93 fermats last theorem, where a gentlemen name bombelli created a new number called i for imaginary numbers, and you will see the connection.

i await your reply

genphis
 
genphis said:
read page 93 fermats last theorem, where a gentlemen name bombelli created a new number called i for imaginary numbers, and you will see the connection.

Essentially every poster here is aware of imaginary numbers and can calculate with them.

There is no contradiction here. [itex]\sqrt x[/itex] is the principle square root of x; there will be another square root. A (nonzero) number will have two square roots, three cube roots, four quartic roots, etc.
 
genphis, here's the problem.

All real numbers are either positive, negative, or zero.

A positive times itself is positive.
A negative times itself is positive.
Zero times itself is zero.

But it is not possible to do a ______ times itself is negative.

Imaginary numbers are an extension of the real numbers which fill in that blank.
 
hi tic tac thanks for the thread,

my bug bear is that, if i say 2 x 6 = 12 then why is -2 x -6 not -12.

i know this goes against teachings but, if i increase negativity why does it have to turn positive. why are negative numbers not considered real. if this was an energy analogy
and we were looking at symmetry negative charged-particles are as tangible as there positive counter-parts.

i think the concept of valuing -1 as a value less than 1 and not as a valid number is confusing.

if a temperature is -5 and then it drops 2 x as low it would then be -15 not +15

i know the aforementioned is rambling nonsense but it makes me wonder.

i know numbers are a system for logging and keeping track of info but the negative situation along with the imaginary numbers are perplexing.
 
genphis said:
hi tic tac thanks for the thread,

my bug bear is that, if i say 2 x 6 = 12 then why is -2 x -6 not -12.
Let's back up a step. Would you agree that 2 * (-6) = -12? You can also see this by adding -6 and -6 to get -12. In this case you are "increasing negativity" by doubling -6.

If you agree that 2*(-6) = -12, then it should be the case that the negative of (2*(-6)) should be the negative of (-12). IOW, -(2 * (-6)) = -(-12) = + 12.

The expression on the left side can be written as -2 * (-6) or as 2 *(-(-6)). Notice that it would be incorrect to rewrite it as (-2)*(-(-6)).

genphis said:
i know this goes against teachings but, if i increase negativity why does it have to turn positive.
If you increase negativity, you get something that is more negative; i.e., farther to the left of zero.
genphis said:
why are negative numbers not considered real.
Negative numbers are considered real. However, there are some physical quantities for which it isn't possible to have negative values, such as mass.
genphis said:
if this was an energy analogy
and we were looking at symmetry negative charged-particles are as tangible as there positive counter-parts.

i think the concept of valuing -1 as a value less than 1 and not as a valid number is confusing.
It shouldn't be confusing if you understand how real numbers are laid out on the real number line, like so:
<----(-2)---(-1) ----0------(+1) ------(+2)----->
If you take any two numbers on the real number line, the one to the left is smaller than the one to the right. So -1 < 0 and .5 < 1.1 and so on.
genphis said:
if a temperature is -5 and then it drops 2 x as low it would then be -15 not +15
If a temperature is - 5 degrees (in some scale) and the temperature drops to a number twice as low, the new temp would be -10 degrees. It would not go to -15 degrees, and certainly wouldn't go all the way up to +15 degrees.
genphis said:
i know the aforementioned is rambling nonsense but it makes me wonder.

i know numbers are a system for logging and keeping track of info but the negative situation along with the imaginary numbers are perplexing.
 
my AP Calculus teacher states that she does not like reading F(x)=-x as F(x)= "negative x" because saying negative x implies that the value of x is always negative in which it is not because if the variable x is negative the function is positive. She prefers to read it as "the opposite of x". If you start thinking of negative values as oposite(-6 is the opposite of 6) it can be said that taking -1X-1 is the opposite of 1 times the opposite of one which in turn is taking the opposite of the opposite of 1, which is just 1 not -1
 

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