Does .9-repeating equal 1?

[loinburger]

".9-repeating" meaning "a decimal point followed by an infinite number of 9's." I don't know the VB code for ".9-with-a-bar-on-top."

There's a provably correct answer to this question, but I'm more interested in what the court of public opinion holds to be the truth.

There is no banana option. Bananas aren't math.

Edit: I suppose that I ought to say "a decimal point followed by a countably infinite number of 9's," but I'm afraid that may be begging the question.

[SlowwHand]

I said Yes, but in strictest theory the answer is No.

[Ninot]

I vote no, because it's techincally not.

[SlowwHand]

If you cut off .001 mm off the tip of a banana, it's still close to enough to call it 1 banana.
If you take .001 mm out of a human brain, then no it's not whole.

[LordShiva]

This poll is invalid

[civman2000]

This is such a silly question. It assumes that things like "1" and ".999..." actually have some independent existence from what we say they are (OK, I'll accept for the sake of argument that "1" might, but ".999..."??). The reason that .999...=1 is that that's what we define it to mean. There's no reason we couldn't define it to mean something else though.

[Winston]

Does .9-repeating equal 1?

Of course it does. I can't believe people could disagree with this.

You take 1 and divide it by 3, you get .3 repeating indefinitely. Multiply by 3, and you get .9 repeating indefinitely. Which equals 1.

[civman2000]

Originally posted by Winston

Does .9-repeating equal 1?

Of course it does. I can't believe people could disagree with this.

You take 1 and divide it by 3, you get .3 repeating indefinitely. Multiply by 3, and you get .9 repeating indefinitely. Which equals 1.

That's an essentially circular argument. How do you know that 1/3 is .3 repeating?

[Winston]

No it isn't, it's as straight as can be. Please tell me that you disagree that 1/3 is .3 repeating?

[loinburger]

Better yet, please tell me that you disagree that .3-repeating is a rational number, or else explain what ratio (besides 1/3) defines .3-repeating.

I promised myself that I'd stay in the peanut gallery, but the "math is just meaningless words that I happen to use on a daily basis" argument is just too broad of a target.

[SlowwHand]

How can you possibly introduce the concept of rational here?

[Elok]

Geez, this already sounding like a bloody Platonic dialogue. Anyway, my answer is: "for all practical purposes, yes." Much like pi is, for all practical purposes, 3.141952-something-something. I read somewhere that once you get past a couple dozen decimal places or so, knowing the value of pi more exactly becomes a pointless exercise, since what you already know is enough to calculate the diameter of the sun to the nearest centimeter or something ridiculously accurate like that.

[KrazyHorse]

Re: Does .9-repeating equal 1?

Originally posted by loinburger
There's a provably correct answer to this question, but I'm more interested in what the court of public opinion holds to be the truth

Given that you have a pretty good math background I'm sure you know the answer as well as I do...

[loinburger]

Originally posted by KrazyHorse
Given that you have a pretty good math background I'm sure you know the answer as well as I do...

You keep your so-called "proofs" to yourself, Mr. Elitist Math Guy!

[KrazyHorse]

Originally posted by Ninot
I vote no, because it's techincally not.

Why not?

Take 1-0.99999999.....

What is the answer?