Post: Mathematical Proof that 0.999...=1
10-16-2010, 03:40 AM #1
elfmotat
Rᵤᵥ - ½gᵤᵥR ∝ Tᵤᵥ
(adsbygoogle = window.adsbygoogle || []).push({}); I will prove that 1=0.999999... This one IS NOT a troll (no sneaky tricks like the last one i.e. dividing by zero).

The Fractions Proof

This one requires little to no math knowledge. Note that You must login or register to view this content. represents 0.999999...

One third is equal to 0.33333...

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Three times one third is equal to 1:

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Three times 0.33333... is equal to 0.999999...

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Therefore 1=0.999999...

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The Infinite Series Proof

A number with a repeating decimal can be represented as a sum of an infinite series:

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The formula to find the value of an infinite series where |r|<1 is as follows:

S is the sum, t1 is the first term in the series, and r is the rate.

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Therefore:

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The Algebraic Proof

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Multiply both sides by 10 (remember that when you multiply by ten it shifts the decimal place to the right by one place):

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Subtract x=0.9999... from both sides:

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Simplify:

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Divide by 9:

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The Midpoint Proof

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What is the midpoint (average) between a and b? The formula to find m where m is the midpoint is:

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Using the values for a and b:

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You can use long division to divide 1.9999... by 2 to get m=0.99999...

Since the midpoint between the two points IS one of the two points, the two points MUST be equal. If you are unconvinced that this is true, you could say from the information that:

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Multiply both sides by two:

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Subtract b from both sides:

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Simplify:

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Substituting numerical values:

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The following 3 users say thank you to elfmotat for this useful post:

CRaZyY, Dreamy, IDontbreak
10-19-2010, 09:09 PM #47
Originally posted by Waterguy469 View Post
lol my head hurts ugh...


Yea I agree mate, 7th grade algebra can be a pain in the ass.

The following user thanked George for this useful post:

10-20-2010, 02:25 AM #48
You see where you wrote now subtract x=0.99999 etc.
I think u subtracted wrong because the left side would be 9.0000001
Correct me if im wrong
10-22-2010, 03:20 AM #49
Millz
Worth the Weight
Proof that anything = 0

0 x # = 0
10-22-2010, 03:24 AM #50
Originally posted by elfmotat View Post
I will prove that 1=0.999999... This one IS NOT a troll (no sneaky tricks like the last one i.e. dividing by zero).


You must login or register to view this content.[/QUOTE]
10-22-2010, 04:59 AM #51
I spent an hour trying to find a way to argue against what you said without sounding like an uneducated idiot. I couldn't find a way.

The fraction example really hits home for me...

3 * 1/3 = 1; 1/3 + 1/3 + 1/3 = 3/3 = 1
1/3 = 0.333...; 3 * 0.333... = 0.333... + 0.333... + 0.333... = 0.999...

Therefore we can assume that 1 = 0.999...
10-22-2010, 05:09 AM #52
CRaZyY
Banned
wow thats pretty kool didnt know that
10-22-2010, 07:21 AM #53
Rainbow Dash
Now 20% Cooler
You can't divide by 0?
WHADDAF00K

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