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Phidius (Posted on 2007-05-11) Difficulty: 3 of 5
Prove that

√(1+√(1+√(1+√(1+...))) = 1+1/(1+1/(1+1/(1+...)))

  Submitted by Jer    
Rating: 2.6667 (3 votes)
Solution: (Hide)
The title is a reference to the ancient Greek scuptor after whom the golden ratio was given the symbol phi(Φ).

x = √(1+√(1+√(1+√(1+...)))
x^2 = 1 + √(1+√(1+√(1+√(1+...)))
x^2 = 1 + x
x^2 - x - 1 = 0

The quadratic formula gives phi (1.61803...) as the larger solution.

x = 1+1/(1+1/(1+1/(1+1/(1+1/(1+...
x = 1+1/(x)
x^2 = x + 1
x^2 - x - 1 = 0

Which is the same equation as before.

Comments: ( You must be logged in to post comments.)
  Subject Author Date
SolutionSolutionK Sengupta2007-05-11 14:32:57
Some Thoughtsre(2): Solution ... SpoilerJayDeeKay2007-05-11 13:31:11
Solutionre: Solution ... SpoilerFederico Kereki2007-05-11 12:23:59
SolutionSolution ... SpoilerJayDeeKay2007-05-11 10:30:45
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