# Phi

**URL:** <https://boards.straightdope.com/t/phi/251642>\
**Category:** Cecil's Columns/Staff Reports\
**Created:** [June 22, 2004, 3:26pm UTC](https://boards.straightdope.com/t/phi/251642 "2004-06-22T15:26:47Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![realtimesw](https://avatars.discourse-cdn.com/v4/letter/r/6a8cbe/32.png) [@realtimesw](https://boards.straightdope.com/u/realtimesw)\
**Post date:** [June 22, 2004, 3:26pm UTC](https://boards.straightdope.com/t/phi/251642/1 "2004-06-22T15:26:47Z")

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I just read the comment on the The Da Vinci Code. I haven’t read the book and this is my first view of Cecil so-called ‘straight’ dope. In fact Phi has some other strange properties:

It is caclulated by (square-root (5) - 1) / 2, the reciprical is obtained by subtracting 1 and the square by adding 1.

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**Author:** ![RM\_Mentock](https://avatars.discourse-cdn.com/v4/letter/r/e274bd/32.png) [@RM\_Mentock](https://boards.straightdope.com/u/RM_Mentock)\
**Post date:** [June 22, 2004, 4:04pm UTC](https://boards.straightdope.com/t/phi/251642/2 "2004-06-22T16:04:51Z")

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> [@realtimesw](#):
>
> I just read the comment on the The Da Vinci Code. I haven’t read the book and this is my first view of Cecil so-called ‘straight’ dope. In fact Phi has some other strange properties:
> 
> It is caclulated by (square-root (5) - 1) / 2, the reciprical is obtained by subtracting 1 and the square by adding 1.

In order for that to work out, I think you mean “(square-root (5) +1) / 2”, plus instead of minus.

The column is [Is phi a mystical number as claimed in The Da Vinci Code?](http://www.straightdope.com/columns/040618.html). Welcome to the Straight Dope, hang around awhile. We need more mathmatizers

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**Author:** ![ultrafilter](https://avatars.discourse-cdn.com/v4/letter/u/3d9bf3/32.png) [@ultrafilter](https://boards.straightdope.com/u/ultrafilter)\
**Post date:** [June 22, 2004, 6:08pm UTC](https://boards.straightdope.com/t/phi/251642/3 "2004-06-22T18:08:08Z")

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Hey there, **realtimesw** , and welcome to the SDMB.

You might be interested in the discussion over [here](http://boards.straightdope.com/sdmb/showthread.php?t=262245).

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**Author:** ![Darklon](https://avatars.discourse-cdn.com/v4/letter/d/46a35a/32.png) [@Darklon](https://boards.straightdope.com/u/Darklon)\
**Post date:** [June 23, 2004, 6:44am UTC](https://boards.straightdope.com/t/phi/251642/4 "2004-06-23T06:44:47Z")

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Oddly, all this ‘significance’ reminds me of the law of fives somehow. 🙂

[http://www.principiadiscordia.com/book/23.php](http://www.principiadiscordia.com/book/23.php)

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**Author:** ![Mathochist](https://avatars.discourse-cdn.com/v4/letter/m/c89c15/32.png) [@Mathochist](https://boards.straightdope.com/u/Mathochist)\
**Post date:** [June 23, 2004, 9:43am UTC](https://boards.straightdope.com/t/phi/251642/5 "2004-06-23T09:43:28Z")

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> [@Darklon](#):
>
> Oddly, all this ‘significance’ reminds me of the law of fives somehow. 🙂
> 
> [Principia Discordia - Page 16](http://www.principiadiscordia.com/book/23.php)

Weak or strong form (as delineated by Hagbard Celine)?