Thread: .9999...=1
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Old November 26th, 2012, 10:21 AM   #21 (permalink)
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Originally Posted by psionandy View Post
thats only true if you assume 0.3333... = 1/3
which (depending on context, may or may not be true
1/3 is exactly = .333... repeated for ever and you can easily discover that for yourself by dividing 1 by 3. If you do it manually using the standard you will constantly get repeating 3's forever until you decide you've had enough punishment.

I wanted to avoid the use of higher mathematics, but the reason behind the equality is stated right in the wiki article:

The equality of 0.999... and 1 is closely related to the absence of nonzero infinitesimals in the real number system, the most commonly used system in mathematical analysis.
The equality 0.999... = 1 has long been accepted by mathematicians and is part of general mathematical education. Nonetheless, some students find it sufficiently counterintuitive that they question or reject it, commonly enough that the difficulty of convincing them of the validity of this identity has been the subject of several studies in mathematics education
Whether anyone chooses to accept it or not is their choice, but nonetheless, it is 100% true. I often run into non-believers when I teach this topic in the Infinite Series part of Calculus II, granted the proof for that class is different giving the context of the class.
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Last edited by jhawkkw; July 30th, 2013 at 11:22 AM. Reason: Don't Feed the Trolls
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