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I love all the people who were condescending in their belief that 1.9999 was different than 2.

Here's a tip kids, if you claim educational superiority, be sure you're right.
 
In my first university calculus class, the professor wrote on the board:

0.999... infinity
1

And asked us if they were different numbers. Per her argument, they are not, since there's no number in between 0.999... and 1. Ergo, they're the same. Or, more technically,

Then is .8888infinity the same as .99999infinity? therefore .8888888infinity equals .99999999infinity? Since there is no number in between? a remainder exists doesn't it? though It is a remainder that is as irrational as the two numbers it is between in this case, just as it is an irrational number between .99999 inf and 1. Using the logic that .999999infinite is the same as 1 somebody could argue that all decimals of this nature are equal to one by relation that they are equal to each other in sequence. in this case there is always a roughly 1/10th or 1/10th of infinity of an amount missing not making it actually 1 but almost 1. Stating that it absolutely equals 1 is just for convenience sake I remember one important lesson my calculus professor taught us about practicality that even the best of mathematicians are lazy so 1=.99999999etc for practical purposes, but those who were going on to study in certain fields like quantum physics the matter that such things are different. Numbers have plenty of importance when it comes to calculating on the smallest known scales. My calculus was horrible in practice (writing out the math)when I was taking these courses, but my understanding of the math (comprehension and analysis of others work) was good enough to grasp the concepts of the field. A physicist cannot be lazy as a mathematician can. The deeper they go the more they have to know and apply to the experiments to properly interpret the data correctly. Rounding things does not work well at the quantum level for accuracy even if things have to be rounded the information is more accurate the more decimal places are used in which it is able to be calculated.
 
Yea, never mind:rolleyes:

Burden is on YOU to proof they are not the same after proofs proving they are the same have been established

Also, feel free to look up all the references on the topic the wiki conviently provides proving they ARE The same by the way

Reference something juried for the proofs, that's all I'd like to see for a change Wikipedia is notoriously chaotic. But that doesn't necessarily make it true either are the references primary? secondary?....?
 
I'm having a great discussion with a friend about the following...

1. if x=1.999...infinity, then 10x=19.999...infinity. Subtracting 10x from x gives 9x=18. Dividing both sides results in x=2.

2. Using your calculators on this one. 1/9=0.111...?. 2/9=0.222....?. 3/9=0.333...?. 4,5,6,7,8 follow the same pattern. What, then is 9/9? It is 0.999...infinity.

Do you think those are valid? I think they are and thinking in infinite terms 1.999...infinity is equal to 2.

My friend thinks he can add any number to infinity because he just can.

Food for thought. Any you want to add?

I arrived here late but...

You both need to go back to school and at same time pay attention to the movie Contact.

You are dividing prime numbers who just can be divided between themselves and 1. Like the signals in the movie where prime numbers.

And 9 between 9 is 1, not 0,9999.

Pay attention to the numbers and do not guess because you will have loads of financial problems IF you ever manage to get enough money to get one.
 
Think about this in the form of conics (using cones) When a cone is stretched to infinity it becomes a cylinder...
 
k don't know if anyone said this.
INFINITY IS NOT A NUMBER

my teacher has a shirt that says this.
o and repeating digits has a vinculum on top of it, not w/e infinity.

to indicate a properly repeating digit ... is sufficient.

OP, what math have you taken

omg, im not even going to try, im seeing all kinds of messed up things here. dam people. unsubscribe. i don't even want to know what happens with this.
 
Think about this in the form of conics (using cones) When a cone is stretched to infinity it becomes a cylinder...
How so? maybe a section of the cone seems like a cylinder but there is still a slight angle--perceptibly yes it is for all practical purposes a cylinder, But as part of the whole not the section at some point as it is being infinitely stretched it is still a cone.
 
Reference something juried for the proofs, that's all I'd like to see for a change Wikipedia is notoriously chaotic. But that doesn't necessarily make it true either are the references primary? secondary?....?

Doesn't matter. That Wiki page references a number of simple, easy to follow proofs (we'll call 'em proofs for now) that demonstrate that 0.(9) = 1.

This is not a debatable subject. By mathematical definition, 0.(9) = 1.

And no, 0.9~ is not an irrational number. Because it = 1.

There is no last 9. Your gut is telling you that there is a last 9 in the sequence, because infinity is a difficult concept to understand on an intuitive level. What's happening here is your intuition is overriding your intellect.

You said you took calculus. Review your definition of a limit, then infinity. The maths are there, as plain as day, yelling at you that 0.(9) = 1. You're just not listening because you're looking for the last 9.
 
k don't know if anyone said this.
BUT INFINITY IS NOT A NUMBER

my teacher has a shirt that says this.
o and repeating digits has a vinculum on top of it, not to the infinity.

Only using that infinity thing to relate homie. I just couldn't find the little line over the number in key caps on my mac. Like I said I am bad at writing the math but I do interpret others data very well--you are correct infinity is not a number it is more an expression or concept if you will of something neverending--I was terrible at story problems in mathematics too I won't lie. Saying "to the infinity" is an easier way to convey the concept to stoners of something that goes on and on such as this .99999 debate thingy will--it will probably outlast humanity itself (if some other intelligence should bother with it).
 
Doesn't matter. That Wiki page references a number of simple, easy to follow proofs (we'll call 'em proofs for now) that demonstrate that 0.(9) = 1.

This is not a debatable subject. By mathematical definition, 0.(9) = 1.

And no, 0.9~ is not an irrational number. Because it = 1.

There is no last 9. Your gut is telling you that there is a last 9 in the sequence, because infinity is a difficult concept to understand on an intuitive level. What's happening here is your intuition is overriding your intellect.

You said you took calculus. Review your definition of a limit, then infinity. The maths are there, as plain as day, yelling at you that 0.(9) = 1. You're just not listening because you're looking for the last 9.

it's a chase I am not looking for a last 9 I just keep chasing knowing i'll never reach an end
 
True or false? - "A regular polygon with an infinite number of sides is a circle."

Here's why it's true:
Consider the original question in this thread. When we say that 1=0.9... or that 1 is 0.9..., the definitions of "=" and "is" are "there is no difference between the values".

One way we know that there is no difference is that if you tell me any number D>0, I can show that the absolute value of the difference is smaller than D. In other words, I can show you that you are wrong if you pick any positive value. Therefore, the difference D can't be more than zero, so it must be zero.

In the same way, if you tell me any number D, I can make an N-sided regular polygon inscribed in a unit circle so that the difference in area between the circle and the polygon is less than D. All I have to do is make N big enough. Therefore, by making the number of sides infinite, I can arrange that polygon=circle.​

Here's why it's false:
By definition, a regular polygon is a figure in a plane consisting of a finite number of end-to-end line segments that have equal lengths and form equal angles. (There are many other ways to say this.)

Therefore, an infinite polygon can't exist by definition.​
So apparently the statement is false even though you can prove that it's true. ;)
 
Then is .8888infinity the same as .99999infinity? therefore .8888888infinity equals .99999999infinity?

I think 0.888 (repeating) is (apparently) equal to 0.9, not 0.99999 (repeating).

But, Doctor Q, care to explain how D=0, when you said that D>0? I mean, does D stand for a specific unit in your polygon problem, or just any variable?

Like, would it be the same if I said X>0, and you proved me wrong by saying that X=0?
 
I think 0.888 (repeating) is (apparently) equal to 0.9, not 0.99999 (repeating).

But, Doctor Q, care to explain how D=0, when you said that D>0? I mean, does D stand for a specific unit in your polygon problem, or just any variable?

Like, would it be the same if I said X>0, and you proved me wrong by saying that X=0?

Fireshot, think about it this way, which also addresses an error in your post.

What positive numerical value fits between 0.(9) and 1?

What positive, numerical value fits between 0.(8) and 9? It's greater than 0, therefore, the two are not equal. 0.8(9) = 0.(9), not 0.(8)
 
Fireshot, think about it this way, which also addresses an error in your post.

What positive numerical value fits between 0.(9) and 1?

What positive, numerical value fits between 0.(8) and 9? It's greater than 0, therefore, the two are not equal. 0.8(9) = 0.(9), not 0.(8)

Ah yes, I meant 0.8999..repeating, not 0.9.My fault.
 
True or false? - "A regular polygon with an infinite number of sides is a circle."

Here's why it's true:
Consider the original question in this thread. When we say that 1=0.9... or that 1 is 0.9..., the definitions of "=" and "is" are "there is no difference between the values".

One way we know that there is no difference is that if you tell me any number D>0, I can show that the absolute value of the difference is smaller than D. In other words, I can show you that you are wrong if you pick any positive value. Therefore, the difference D can't be more than zero, so it must be zero.

In the same way, if you tell me any number D, I can make an N-sided regular polygon inscribed in a unit circle so that the difference in area between the circle and the polygon is less than D. All I have to do is make N big enough. Therefore, by making the number of sides infinite, I can arrange that polygon=circle.​

Here's why it's false:
By definition, a regular polygon is a figure in a plane consisting of a finite number of end-to-end line segments that have equal lengths and form equal angles. (There are many other ways to say this.)

Therefore, an infinite polygon can't exist by definition.​
So apparently the statement is false even though you can prove that it's true. ;)

That's horse puckey, man.

Looked at simply, how large is the set of all even numbers? How large is the set of all numbers divisible by 43564?

How large is the set of all regular polygons? Take the last one in the set. That's your circle ;)
 
That's horse puckey, man.

Looked at simply, how large is the set of all even numbers? How large is the set of all numbers divisible by 43564?

How large is the set of all regular polygons? Take the last one in the set. That's your circle ;)
Sets have "last ones"? You learn something new every day! :)
 
Looked at simply, how large is the set of all even numbers? How large is the set of all numbers divisible by 43564?

Those two sets have the same cardinality, that is, they have the same size. The reason is that there is a bijective map from one set to the other, namely 2x gets mapped to 42564x.

It doesn't matter that one set is a subset of the other. Quite weird.
 
Those two sets have the same cardinality, that is, they have the same size. The reason is that there is a bijective map from one set to the other, namely 2x gets mapped to 42564x.

It doesn't matter that one set is a subset of the other. Quite weird.

This goes back to the thing about there being no last 9. Most people don't have a good grasp on the concept of of infinity and this is one of those issues that trips them up.

I know plenty of engineers that can't grasp that the set of all even numbers is the same size as the set of all whole numbers. To me, this is a good mathematical shibboleth on whether a person actually fundamentally grasps calculus or if he is just a technician with a degree who does what the numbers tell him to do.
 
This goes back to the thing about there being no last 9. Most people don't have a good grasp on the concept of of infinity and this is one of those issues that trips them up.

I know plenty of engineers that can't grasp that the set of all even numbers is the same size as the set of all whole numbers. To me, this is a good mathematical shibboleth on whether a person actually fundamentally grasps calculus or if he is just a technician with a degree who does what the numbers tell him to do.
What if anything anyone has said leads you to an assumption that people are looking for a "last number" in a decimal that clearly is on going (eternal, forever, infinitely, whatever the term for endless in general you want to nitpick about concerning definitions) and still not so clearly equal to one _ pretty damn close by a constantly narrowing margin but still not 1 this .9 thing is a bit of mystery otherwise until someone figures out a way to express it accurately. You speak as if all the rules of numbers have been established and there is nothing that's going to change them. This is a case of an anomaly where no solid rule has been figured out so for sheer laziness on the part of mathematicians for the time being 1=.9(and so on) for practical purposes.
 
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