Alright fine. Let me rephrase then. you can't subtract infinity, even if is an infinite number of decimal places. The whole infinity thing I was talking about was 9.9999R - .9999R = 9. You can't do that. That was subtracting infinity. You get it now?
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Alright fine. Let me rephrase then. you can't subtract infinity, even if is an infinite number of decimal places. The whole infinity thing I was talking about was 9.9999R - .9999R = 9. You can't do that. That was subtracting infinity. You get it now? no, i don't "get it". could you explain why it cannot be done. and you never addressed this: if two numbers can be so close that no number is in between them, what comes before 0.9R? |
"nd you never addressed this: if two numbers can be so close that no number is in between them, what comes before 0.9R?"
ummm, .9R with an 8 at the end ;) |
where would 0.9R with an 85 on the end fit in there?
you couldn't have anything "after" the infinite number of nines because there is no end to place it after. if you're placing a digit on the end of that decimal, you're stopping the nines somewhere, which means that you're not dealing with 0.9R anymore, you're dealing with a finite number of nines. you could admit that there is no number that comes before 0.9R but is so close that there are no numbers between them; nothing said that such a number had to exist. but, why would 0.9R and 1 be the only numbers (aside from 1.9R and 2, etc.) that have no number in between them? |
You're right. I think the modified version would be something like .999R + 8/inf. I wonder if that number exists, but it's the closest I can think of. Eventually on the numberline, as you go to infinity, numbers won't have anything in between them. There's thousands of examples. It isn't just I.9R, 2.9R, etc. It could be 1.19R being next to 1.2, 1.1119R being next to 1.112, 1.3459R being next to 1.346. Those are the ones that are easiest to be defined. Now i'm sure that the ones that are harder to define ( ex. what is before .9R ) do actually exist. By the way Fish, i'm getting a little bored with you just asking questions. Jp asked you a question. Why don't you answer that or something. Just in conclusion, i'll summarize one of my old main arguments. .999R isn't 1, it just infinitely gets closer. Hypothetically, it's like standing 10 feet from a wall and always walking a fraction of the distance. Now, in theory, you should never reach the wall. Of course you couldn't try this in real life because it is impractical, however theoretically it works. It's the same concept.
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By the way Fish, i'm getting a little bored with you just asking questions. i ask questions because you don't explain your reasoning for thinking what you think. if you do have some reasoning, then you should be able to answer the questions no problem. Jp asked you a question. Why don't you answer that or something. jp asked a question about the one series being "one nine ahead", but each series has an infinite number of terms which can be mapped to the set of integers. most of his points rely on 0.0R1 somehow existing and being different than 0. if 0.9R = 1, then this "0.0R1" would equal zero. if you assume that something is right when its actually wrong, you can "prove" a lot of things. Now i'm sure that the ones that are harder to define ( ex. what is before .9R ) do actually exist. what would those numbers be? if they exist, they can be found. I think the modified version would be something like .999R + 8/inf the limit of 8/x as x goes to infinity is zero. you can't plug infinity in for x, but you can find the value that 8/x approaches. Hypothetically, it's like standing 10 feet from a wall and always walking a fraction of the distance. Now, in theory, you should never reach the wall. Of course you couldn't try this in real life because it is impractical, however theoretically it works. It's the same concept. as i've explained to you before, it doesn't work because of the time constraints. taking a step takes a certain amount of time, and people only live so long. it takes no time for 0.9R to have decimal places, so its not the same concept. your example has a problem that this mathematical idea does not have. also, 0.9R is not equivalent to just walking any old "fraction of the distance". if each step moved you 1/10th of the way closer to the wall, you would never hit it, like how 0.1R != 1. you'll never understand things like this if you always want a physical example. |
"i ask questions because you don't explain your reasoning for thinking what you think. if you do have some reasoning, then you should be able to answer the questions no problem"
It's not that, it just feels like i'm talking and getting no where. I mean, i've convinced a few people, but you seem like the type that'll keep this going forever unless it's closed. "the limit of 8/x as x goes to infinity is zero. you can't plug infinity in for x, but you can find the value that 8/x approaches." Same concept. 8/inf approaches 0. It's just so damn small but still not zero "as i've explained to you before, it doesn't work because of the time constraints. taking a step takes a certain amount of time, and people only live so long. it takes no time for 0.9R to have decimal places, so its not the same concept. your example has a problem that this mathematical idea does not have. also, 0.9R is not equivalent to just walking any old "fraction of the distance". if each step moved you 1/10th of the way closer to the wall, you would never hit it, like how 0.1R != 1." I thought you'd get it if I reworded it. Notice I said hypothetically, meaning in theory. It's a physical comparison, but I didn't mean you actually try it. It's just something to compare it to. And yes, any fraction between 0 and 1 would work. It's the idea of it going to infinity but never hitting the wall. You'd be saying that it would hit the wall. Now, i'll say it again, maybe you'll get it this time..... IN THEORY, NOT IN PRACTICE. "you'll never understand things like this if you always want a physical example." you'll never understand things like this if you are dismiss the example because of your silly time constraints. |
It's not that, it just feels like i'm talking and getting no where. I mean, i've convinced a few people, but you seem like the type that'll keep this going forever unless it's closed. you could convince people that grass is purple, silly me for refusing to believe it. if you want to convince me of something, stop saying "you can't do that", or "that doesn't work" and show me what's wrong with it or why it doesn't work. you said that you can't do "9.9999R - .9999R = 9", why not? there are infinite digits after the decimal point, but they are all the same. when you subtract them, why wouldn't those decimal places all cancel out? again, this is related to the example you keep giving: yes, the decimal places keep going, but they all cancel out and you're just left with "9.0". you couldn't write out the subtraction by hand, but you can see that if all of the digits after the decimal place are identical that it would result in a zero to the right of thed decimal. if you disagree with that, please explain why. if you can't explain why, or if you refuse to explain, then don't complain that people don't understand you, because you're not giving me any reason to believe you. if you can't explain it, how do you know its right? this is math, we're not taking leaps of faith, we're crunching numbers. i'm not asking these questions to bother you. you'll never understand things like this if you are dismiss the example because of your silly time constraints. i understand what you're saying, but those constraints are what makes your example not work. because those constraints only apply to your hypothetical situation and not to the actual math, its not a very good example. It's just something to compare it to if you want to say that its wrong or impossible, then you could have compared it to anything that is wrong or impossible. its not impossible just because you compared it to something that's impossible. the time constraints aren't silly, that's what makes your example a terrible comparison. not all examples are good ones, and making them "hypothetical" doesn't mean that they can't be wrong. any fraction any fraction? what's 0.9R as a fraction? ;-) |
Alright, all explain why you can't subtract infinity. Because it is not a constant. It represents something that never ends. So how do you know that you can just subtract it? What would it be since it's not a constant? 1? 2? 3? You can't know for sure. And you say they have to all cancel out? How do you know they cancel out to 0? Why don't you explailn that? And i'll say it again, dont just say it's a constant, because it isn't. Or because it's looks the same after the decimal point.
" understand what you're saying, but those constraints are what makes your example not work. because those constraints only apply to your hypothetical situation and not to the actual math, its not a very good example." I suppose it's not a good example because someone like you would add an unneeded factor ( time ) to the problem so that you can dismiss it as a bad problem, and then ask questions about it. Assuming time was infinite, answer the question, you would never get to the wall, would you? Same thing here. You never get to 1. "any fraction? what's 0.9R as a fraction? ;-)" Any number between 0 and 1 then. And any number can be made into a fraction, besides 0 and infinity of course. 9.9R / 10 maybe? <_< Goddamn, stop with the annoying specifics. You already should know that I mean number. And if it isn't directly said, then use your math skill to figure out that any number can be made a fraction. |
Solbadguy500, please explain how you can determine if a number given in decimal form is rational or not.
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Well something like .875 is rational because it is 7/8. But something like .8430873209475745934..... isn't because you can't determine the fraction other than something like 8.43087.../10. He was being vague, so I played into it. I know what rationality is.
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Alright, all explain why you can't subtract infinity. Because it is not a constant. It represents something that never ends. So how do you know that you can just subtract it? What would it be since it's not a constant? 1? 2? 3? You can't know for sure. you're not subtracting infinity, you're subtracting a number with infinite digits. 0.9R is a constant, and you can subtract it from 0.9R. if even you can't imagine doing the subtraction, you're subtracting a number from itself, so you'd get zero. 0.3R = 1 / 3, but you can certainly subtract one third from something. And you say they have to all cancel out? How do you know they cancel out to 0? Why don't you explailn that? all of the decimal places are nines. nothing changes, so you can hopefully see a pattern here: 0.9 - 0.9 = 0 0.99 - 0.99 = 0 0.999 - 0.999 = 0 you keep adding nines to each number, so they continue to cancel out. jp's argument was that since you multilpy 0.9R by 10, it has one less decimal place than 0.9R because one of the nines from the right side of the decimal place is now on the left. so, when subtracted, it wouldn't be "9.9R - 0.9R = 9.0" because of the "extra nine". but, both have an infinite number of nines, and its the same degree of infinity. the limit of x/(x+1) as x goes to infinity is 1. as x goes to infinity, x = x + 1 so x / (x + 1) = 1. even though x+1 is "one ahead" of "x", they both go to the same infinity. |
"0.9R is a constant, and you can subtract it from 0.9R"
I guess that's the main reason we see this differently. I view 0.9R as going to infinity, and since you don't, let's just agree to disagree. |
I view 0.9R as going to infinity, again, it doesn't go to infinity. it has an infinite number of decimal places, but that is very different that something that "goes to infinity". infinity doesn't have a value like 3 or 7 do, but 0.9R does have a value. the value of 0.9R is somewhere between 0 and 1 (inclusive :-P), so why couldn't you subtract it from something else? pi has an infinite number of digits, but you can still subtract pi from something. the square root of two also has an infinite number of digits, but you can do addition and multiplication with it. 0.3R also has an infinite number of digits, but would you say that you can't subtract one third from something? let's just agree to disagree. i don't like to think of what i do as disagreeing, but being correct. |
I was trying to get you to drop it. But since you responded, so will I. .9R goes to infinity since it has infinite 9's. Is that concept so hard to get?
" the value of 0.9R is somewhere between 0 and 1 " It seems this argument is done though. You agree with me. 0.9R is between 0 and 1. "i don't like to think of what i do as disagreeing, but being correct." You're correct now since you finally agreed with me. 0.9R is it's own separate number. You even admitted it up there. The winner is me. You go to hell. Burn |
.9R goes to infinity since it has infinite 9's. Is that concept so hard to get? there's a difference between having an infinite number of decimal places and "going to infinity". as x increases, the value of f(x) may go to infinity. the value of 0.9R (whatever you think it is) will not change. even if you don't think its 1, you'd agree that its less than 10. 0.9R is always less than 10, so it can never "go to infinity" if it can never go above 10. like i've mentioned before (and you've never addressed it), why can you not do math with a number that has an infinite number of digits? you never explained that, you just said (repeatedly) that it cannot be done. however, its done all the time. one third, pi, and the square root of two all have an infinite number of digits, but they occur in math rather often. how can you subtract 0.3R from something but not be able to subtract 0.9R from something? It seems this argument is done though. You agree with me. 0.9R is between 0 and 1. i said "inclusive", meaning that the value could be anything between zero and one, *including* zero and one. calling this an argument is giving you much more credit than you deserve. "nuh uh" is not much of an argument. |
"there's a difference between having an infinite number of decimal places and "going to infinity". "
The 9's go to infinity. Seriously, I thought that would be easy to figure out. Either i'm not arguing with the sharpest tool in the shed, or you're just trying to avoid it. "like i've mentioned before (and you've never addressed it), why can you not do math with a number that has an infinite number of digits? you never explained that, you just said (repeatedly) that it cannot be done. however, its done all the time. one third, pi, and the square root of two all have an infinite number of digits, but they occur in math rather often. how can you subtract 0.3R from something but not be able to subtract 0.9R from something?" I wouldn't agree that pi minus pi would necessarily be 0, assuming the digits are infinite. I don't know whether pi is infinite or not. It probably is. But in math, the differences are so negligible that you just assume that 3.33333R - .33333R = 3. even though, if you were to keep subtracting like that, you'd get .0000R1. But in a problem, that kind of little thing doesn't matter. When discussing the absolute value here, it does. How else do you want me to explain why you can't subtract infinity. I thought I already have, but i'll make it more formal. Infinity isn't a constant, it's a concept. When I was doing limits in calculus, it was tempting to subtract infinities. But our teacher says that calculus doesn't allow for it. Since infinity isn't a defined number, you wouldn't know what the answer would be when you subtract them, so it is futile. That's what I learned, and it makes sense. "i said "inclusive", meaning that the value could be anything between zero and one, *including* zero and one." All right, i'll give you credit for that, I didn't see that. "calling this an argument is giving you much more credit than you deserve. "nuh uh" is not much of an argument." That's pretty low, calling my argument a "nuh uh" and saying I don't deserve this. Who defined you as being right? Don't act so judgemental without thinking about your own agrument first. |
Infinity isn't a constant, it's a concept. When I was doing limits in calculus, it was tempting to subtract infinities. But our teacher says that calculus doesn't allow for it. Since infinity isn't a defined number, you wouldn't know what the answer would be when you subtract them, so it is futile. That's what I learned, and it makes sense. you're correct there, but, 0.9R is not infinity. it has an infinite number of digits, but its value does not "approach infinity" in the same sense that functions "approach infinity" when you're dealing with limits. when you were talking about limits, you'd say that things approach infinity as x goes to infinity. there is no "x" in 0.9R, so, 0.9R is a constant. the value of 0.9R, whatever it is, does not change. its not a function, its a constant term. you might think the value increases as you add nines onto the end of it, but, you're not really adding nines onto it. 0.9R already has an infinite number of nines. if you were to keep subtracting like that, you'd get .0000R1 how could you have 0.0R1? how can there be a digit that comes after an infinite number of zeroes? that "1" can't come after the last zero because there is no "last zero". you're starting to explain your reasoning now, which makes it a lot easier to understand you. |
i have no idea what you're talking about there. i was not subtracting infinity, i was subtracting an infinite series. 0.9R is not infinity, it just has an infinite number of decimal places. if the amount of decimal places bothers you, since its a repeating decimal you should just write it as a fraction instead.
there isn't an extra nine, all terms in the series can be mapped to the set of integers.