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Poll: Does point 9 recurring equal one?

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Re: Poll: Does point 9 recurring equal one?

#21
At first I was thrown off by the way you wrote the value.

If "point 9 recurring" means the same thing as:

the limit of the sequence 0.9, 0.99, 0.999, etc.

then I know it equals 1 because that's what I was told.

Math in engineering school was like studying hammers. You don't take them apart, and you don't ask why. You just grab one and start hitting things. For five years.

Re: Poll: Does point 9 recurring equal one?

#22

None of the choices above work. The LIMIT of .9999 is 1. Since .9 repeating is not actually the same number as .9 with an infinite number of nines at the end, you're always adding a nine out there to do something with it, right? Sure .9 repeating infinitely is the same as one, but I'd argue that .9 with the repeating symbol is not, since the symbol indicates that the repeating has to take place manually. The repeatin…

This downmodding is not making me any less cranky. (grin)

Re: Poll: Does point 9 recurring equal one?

#24
post #11

1/3 = .333333.... 1/3 + 1/3 + 1/3 = 1 So, yes

I've always used this variation

  1/9 = 0.111...
  0.111... + 0.111... + ... = 0.999....
  9 * 1/9 = 1
Or we could use base 9, instead of base 10 to get rid of that infinite sequence of digits that seem to confuse people so much.

  1/10 = 0.1
  10 * 1/10 = 1

Re: Poll: Does point 9 recurring equal one?

#25
post #16

According to math folk, yes. According to philosophy folk, no. This crowd is more likely to be math folk. Both crowds just need to get out and relax more.

Many "philosophy folk" are very comfortable with the type of logical argument that leads us to the conclusion that 0.999... == 1, and most of the others will defer the question to mathematicians.

Re: Poll: Does point 9 recurring equal one?

#26

Why are you interested in getting people's opinions on a matter of fact? "Everyone is entitled to their own opinions, but they are not entitled to their own facts."

Some people regard it as "fact" that the Moon landings were faked. Some people regard it as "fact" that they've been abducted by aliens. Some people regard it as "fact" that they can power their car with water. Some people regard it as "fact" that there is only one size of infinity. Some people regard it as "fact" that you can choose one element from each of infinitely many non-empty sets. Some people regard it as "f…

your colleague is 99.9...% wrong

Re: Poll: Does point 9 recurring equal one?

#28
post #18

it approaches 1 but is not equal to 1.

(sorry to see you downvoted - because it is actually sometimes tought to grasp but...) it doesnt approach one- your thinking of a nice graph where the line does approach but never touch, however 0.9... is NOT a function, cannot be plotted. It exists for infinite length. Any distance it is from 1 is constant.

yes and sometimes the integrals of those graphs converge on a value...

Re: Poll: Does point 9 recurring equal one?

#29
post #18

it approaches 1 but is not equal to 1.

(sorry to see you downvoted - because it is actually sometimes tought to grasp but...) it doesnt approach one- your thinking of a nice graph where the line does approach but never touch, however 0.9... is NOT a function, cannot be plotted. It exists for infinite length. Any distance it is from 1 is constant.

I interpreted repeating 9's as:

the function that writes some number of repeating 9's (replacing the zero in the last decimal place with a 9). This function approaches 1, does it not?

f(1) = 0.9

f(2) = 0.99

f(3) = 0.999

so f as defined above approaches 1

I interpreted the question in the context of numerical precision. Since we are usually not dealing with infinite precision, the two are not equal.

I am familiar with the obvious: 1/3 == 0.3333... and 3 * 1/3 == 1 so 0.9999... == 1

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