Proving a Sequence of Extension Fields for $\sqrt{1+\sqrt{2}+\sqrt{3}+\sqrt{5}}$

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Homework Help Overview

The discussion revolves around finding a sequence of extension fields that includes the element \(\sqrt{1+\sqrt{2}+\sqrt{3}+\sqrt{5}}\) within a tower of fields starting from the rational numbers \(Q\). Participants are tasked with proving that each step in this sequence is non-trivial, except for the last one.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants explore the construction of extension fields, with one suggesting a sequence starting from \(F_0 = Q\) and progressing through \(F_1\) to \(F_4\). There is confusion regarding the interpretation of the problem, particularly about whether the sequence should continue indefinitely.

Discussion Status

The discussion is ongoing, with participants sharing their interpretations and attempts at constructing the sequence. Some guidance has been offered regarding the triviality of certain steps, but there is no explicit consensus on the interpretation of the problem's requirements.

Contextual Notes

Participants have noted that the notation used in the original post may have caused confusion, particularly regarding subscripts and the nature of the sequence. There is also a mention of a potential misunderstanding about the sequence's length and whether it should extend indefinitely.

saadsarfraz
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Homework Statement



Find a sequence of extension fields (i.e. tower)
Q= F_{0}\subseteq...\subseteqF_{n}.

where \sqrt{1+\sqrt{2}+\sqrt{3}+\sqrt{5}} \in F_{n}

Prove that all the steps are non-trivial. except the last one. btw Q is the set of rational number. and 0 and n on F were meant to be subscripts not superscripts (i don't know how to do that)

Homework Equations





The Attempt at a Solution



I'm a bit confused as to what to do in this question? I don't think I understand the question.\sqrt{}
 
Last edited:
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The "trivial" step is F_1= Q(\sqrt{1}) since \sqrt{1}= 1 which already is a rational number. Take F_2= F_1(\sqrt{2})= Q_(\sqrt{2}), F_3= F_2(\sqrt{3}), etc.
 
Last edited by a moderator:
ok i think i got it, can anyone please check my answer

K_0 = 2 which corresponds to F_0
K_1= 1 + \sqrt{2} for F_1
K_2= 1 + \sqrt{2} + \sqrt{3} for F_2
K_3= 1 + \sqrt{2} + \sqrt{3} + \sqrt{5} for F_3
K_4= \sqrt{1+\sqrt{2}+\sqrt{3}+\sqrt{5}} for F_4except the last one is supposed to go on forever? can anyone help me in this.
 
Your original question did not "go on forever", it stopped at \sqrt{5}.
 

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