Imaginary numbers negative confusion

In summary, the conversation discusses the confusion and misconceptions surrounding the use of negative and imaginary numbers in mathematics. The concept of negative numbers is that they are values to the left of zero on the real number line, and multiplying a negative number by a negative number results in a positive number. The use of imaginary numbers is often invoked in mathematical equations to solve problems involving negative values. However, some argue that these numbers are not necessary and can be explained through the concept of "opposite" values.
  • #1
genphis
52
2
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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  • #2
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?
 
  • #3
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
 
  • #4
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.
 
  • #5
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.
 
  • #6
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.
 
  • #7
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.
 
  • #8
my AP Calculus teacher states that she does not like reading F(x)=-x as F(x)= "negative x" becuase 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
 

What are imaginary numbers?

Imaginary numbers are numbers that can be written as a real number multiplied by the imaginary unit, denoted by the letter i. The imaginary unit is defined as the square root of -1.

What is the purpose of using imaginary numbers?

Imaginary numbers are used to represent complex numbers, which cannot be expressed as a real number. They are commonly used in fields such as engineering, physics, and mathematics to solve problems that involve quantities with both real and imaginary components.

Why do people get confused between imaginary numbers and negative numbers?

People often confuse imaginary numbers with negative numbers because the square root of a negative number is considered an "imaginary" concept. However, imaginary numbers and negative numbers have different properties and behave differently in mathematical operations.

What is the difference between imaginary numbers and complex numbers?

Imaginary numbers are a subset of complex numbers, which include both real and imaginary numbers. Complex numbers can be written in the form a + bi, where a is the real component and bi is the imaginary component. Imaginary numbers have a real component of 0, making them purely imaginary.

How are imaginary numbers useful in real-world applications?

Imaginary numbers have practical applications in fields such as electrical engineering, signal processing, and quantum mechanics. They are also used in calculating solutions for differential equations and in the study of fractals and chaos theory.

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