(1.0 / 2) process repeated 5 times; what is the algrabraic formula?

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Discussion Overview

The discussion revolves around finding an algebraic formula for repeatedly dividing a number by 2, specifically focusing on the case of dividing 1 by 2 five times. Participants explore different expressions and clarify the nature of these expressions.

Discussion Character

  • Exploratory
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant presents the sequence of divisions: 1 / 2 = 0.5, continuing down to 0.03125, and asks for an algebraic formula.
  • Another participant suggests the expression \(\frac{1}{2^5}\) as a potential formula.
  • A different sequence starting from 64 is introduced, leading to the expression \(\frac{64}{2^{10}}\), with a later correction to \(\frac{64}{2^{11}}\).
  • One participant argues that \(\frac{1}{2^n}\) is a more general formula than \(\frac{1}{2^5}\), which they claim is not a formula but rather an expression.
  • Another participant engages in a discussion about the distinction between an expression and a formula, noting that the original question was about expressing "1 divided by 2 five times" algebraically.
  • A participant elaborates on the relationship between the two sequences and demonstrates how \(\frac{64}{2^{10}}\) can be manipulated to show equivalence to \(\frac{1}{2^5}\) through the rules of indices.
  • Another participant introduces the notation for a product series, suggesting \(\prod_{i=1}^5 \ \frac{1}{2}\) as a representation of the repeated division.

Areas of Agreement / Disagreement

Participants express differing views on what constitutes a formula versus an expression, and there is no consensus on the terminology used. Multiple competing views remain regarding the correct algebraic representation of the repeated division.

Contextual Notes

Some participants note the importance of formatting in mathematical expressions, such as enclosing numbers in braces for clarity. There is also a discussion about the implications of the rules of indices in the context of the presented sequences.

mr magoo
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1 / 2 = 0.5
0.5 / 2 = 0.25
0.25 / 2 = 0.125
0.125 / 2 = 0.0625
0.0625 / 2 = 0.03125

What is the algebraic formula for this?
 
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\frac{1}{2^5}
 
This is a new one;

64 / 2 = 32
32 / 2 = 16
16 / 2 = 8
8 / 2 = 4
4 / 2 = 2
2 / 2 = 1
1 / 2 = 0.5
0.5 / 2 = 0.25
0.25 / 2 = 0.125
0.125 / 2 = 0.0625
0.0625 / 2 = 0.03125

\frac{64}{2^{10}}
 
Last edited:
Thanks.
 
That should actually be \frac{64}{2^{11}}.

Edit: Enclose your "10" in { } to make it appear correctly.
 
Your right, I added one too many and thought there was only ten.
 
Thanks for the editing tip.
 
jgens said:
\frac{1}{2^5}

But that's not a formula.

\frac{1}{2^n} is a formula.
 
Char. Limit said:
But that's not a formula.

I could nitpick and argue that \frac{1}{2^n} is actually an expression and not a formula since it does not contain an equals sign; but the distinction is really not all that relevant. The OP wanted to know how to express "1 divided by 2 fives times" algebraically and one way is \frac{1}{2^5}. I really don't understand the objection.
 
  • #10
mr magoo said:
This is a new one;

64 / 2 = 32
32 / 2 = 16
16 / 2 = 8
8 / 2 = 4
4 / 2 = 2
2 / 2 = 1
1 / 2 = 0.5
0.5 / 2 = 0.25
0.25 / 2 = 0.125
0.125 / 2 = 0.0625
0.0625 / 2 = 0.03125

\frac{64}{2^{10}}

Also notice that since we divided 64 by 2 five times and we got to 1, so \frac{64}{2^5}=1 rearranging, we get 64=2^5 so we can express the answer as

\frac{64}{2^{10}}=\frac{2^5}{2^{10}}

And if you remember the rule of indices, \frac{2^a}{2^b}=2^{a-b} so \frac{2^5}{2^{10}}=2^{5-10}=2^{-5}=\frac{1}{2^5}

As we got in your first question.
 
  • #11
The formula (not sure if this is considered algebraic) or notation for a product series in the original example would be:

\prod_{i=1}^5 \ \frac{1}{2}
 
Last edited:

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