Proof for divisibility of polynomials. [on hold]
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I have no idea how to proceed with the following question. Please help!
"Prove that for any polynomial $ P(x) $ with real coefficients, other than polynomial $x$, the polynomial $ P(P(P(x))) − x $ is divisible by $ P(x) − x $."
polynomials divisibility
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put on hold as off-topic by José Carlos Santos, Sil, John Omielan, TheSimpliFire, RRL 23 hours ago
This question appears to be off-topic. The users who voted to close gave this specific reason:
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$begingroup$
I have no idea how to proceed with the following question. Please help!
"Prove that for any polynomial $ P(x) $ with real coefficients, other than polynomial $x$, the polynomial $ P(P(P(x))) − x $ is divisible by $ P(x) − x $."
polynomials divisibility
New contributor
$endgroup$
put on hold as off-topic by José Carlos Santos, Sil, John Omielan, TheSimpliFire, RRL 23 hours ago
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – José Carlos Santos, Sil, John Omielan, TheSimpliFire, RRL
If this question can be reworded to fit the rules in the help center, please edit the question.
add a comment |
$begingroup$
I have no idea how to proceed with the following question. Please help!
"Prove that for any polynomial $ P(x) $ with real coefficients, other than polynomial $x$, the polynomial $ P(P(P(x))) − x $ is divisible by $ P(x) − x $."
polynomials divisibility
New contributor
$endgroup$
I have no idea how to proceed with the following question. Please help!
"Prove that for any polynomial $ P(x) $ with real coefficients, other than polynomial $x$, the polynomial $ P(P(P(x))) − x $ is divisible by $ P(x) − x $."
polynomials divisibility
polynomials divisibility
New contributor
New contributor
New contributor
asked yesterday
HeetGorakhiyaHeetGorakhiya
303
303
New contributor
New contributor
put on hold as off-topic by José Carlos Santos, Sil, John Omielan, TheSimpliFire, RRL 23 hours ago
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – José Carlos Santos, Sil, John Omielan, TheSimpliFire, RRL
If this question can be reworded to fit the rules in the help center, please edit the question.
put on hold as off-topic by José Carlos Santos, Sil, John Omielan, TheSimpliFire, RRL 23 hours ago
This question appears to be off-topic. The users who voted to close gave this specific reason:
- "This question is missing context or other details: Please provide additional context, which ideally explains why the question is relevant to you and our community. Some forms of context include: background and motivation, relevant definitions, source, possible strategies, your current progress, why the question is interesting or important, etc." – José Carlos Santos, Sil, John Omielan, TheSimpliFire, RRL
If this question can be reworded to fit the rules in the help center, please edit the question.
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2 Answers
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Remember that $$a-bmid P(a)-P(b)$$
so $$P(x)-xmid P(P(x))-P(x)$$ and thus $$P(x)-xmid (P(P(x))-P(x))+ (P(x)-x)$$
so $$P(x)-xmid P(P(x))-xmid P(P(P(x)))-P(x)$$
and thus $$P(x)-xmid (P(P(P(x)))-P(x))+ (P(x)-x)$$
and finaly we have $$P(x)-xmid P(P(P(x)))-x$$
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1
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Modular arithmetic was invented to clarify proofs like this where the divisibilty relation greatly obfuscates the algebraic (operational) essence of the matter - here the simple notion of a fixed point - see my answer.
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– Bill Dubuque
yesterday
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$bmod P(x)!-!x!:, color{#c00}{P(x)equiv x},Rightarrow, P(P(color{#c00}{P(x)}))equiv P(P(color{#c00}{x)}))equiv P(x)equiv x$
Remark $ $ The proof is a special case of: fixed points stay fixed on iteration by induction,
namely: $, $ if $ color{#c00}{f(x) = x} $ then $, {f^{large n}(x) = x},Rightarrow, f^{large n+1}(x) = f^n(color{#c00}{f(x)})=f^n(color{#c00}x)=x$
Corollary $ P(x)!-!x,$ divides $, P^n(x)!-!x,$ for all $,ninBbb N,,$ and all polynomials $,P(x)$
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
Remember that $$a-bmid P(a)-P(b)$$
so $$P(x)-xmid P(P(x))-P(x)$$ and thus $$P(x)-xmid (P(P(x))-P(x))+ (P(x)-x)$$
so $$P(x)-xmid P(P(x))-xmid P(P(P(x)))-P(x)$$
and thus $$P(x)-xmid (P(P(P(x)))-P(x))+ (P(x)-x)$$
and finaly we have $$P(x)-xmid P(P(P(x)))-x$$
$endgroup$
1
$begingroup$
Modular arithmetic was invented to clarify proofs like this where the divisibilty relation greatly obfuscates the algebraic (operational) essence of the matter - here the simple notion of a fixed point - see my answer.
$endgroup$
– Bill Dubuque
yesterday
add a comment |
$begingroup$
Remember that $$a-bmid P(a)-P(b)$$
so $$P(x)-xmid P(P(x))-P(x)$$ and thus $$P(x)-xmid (P(P(x))-P(x))+ (P(x)-x)$$
so $$P(x)-xmid P(P(x))-xmid P(P(P(x)))-P(x)$$
and thus $$P(x)-xmid (P(P(P(x)))-P(x))+ (P(x)-x)$$
and finaly we have $$P(x)-xmid P(P(P(x)))-x$$
$endgroup$
1
$begingroup$
Modular arithmetic was invented to clarify proofs like this where the divisibilty relation greatly obfuscates the algebraic (operational) essence of the matter - here the simple notion of a fixed point - see my answer.
$endgroup$
– Bill Dubuque
yesterday
add a comment |
$begingroup$
Remember that $$a-bmid P(a)-P(b)$$
so $$P(x)-xmid P(P(x))-P(x)$$ and thus $$P(x)-xmid (P(P(x))-P(x))+ (P(x)-x)$$
so $$P(x)-xmid P(P(x))-xmid P(P(P(x)))-P(x)$$
and thus $$P(x)-xmid (P(P(P(x)))-P(x))+ (P(x)-x)$$
and finaly we have $$P(x)-xmid P(P(P(x)))-x$$
$endgroup$
Remember that $$a-bmid P(a)-P(b)$$
so $$P(x)-xmid P(P(x))-P(x)$$ and thus $$P(x)-xmid (P(P(x))-P(x))+ (P(x)-x)$$
so $$P(x)-xmid P(P(x))-xmid P(P(P(x)))-P(x)$$
and thus $$P(x)-xmid (P(P(P(x)))-P(x))+ (P(x)-x)$$
and finaly we have $$P(x)-xmid P(P(P(x)))-x$$
edited yesterday
answered yesterday
Maria MazurMaria Mazur
50k1361125
50k1361125
1
$begingroup$
Modular arithmetic was invented to clarify proofs like this where the divisibilty relation greatly obfuscates the algebraic (operational) essence of the matter - here the simple notion of a fixed point - see my answer.
$endgroup$
– Bill Dubuque
yesterday
add a comment |
1
$begingroup$
Modular arithmetic was invented to clarify proofs like this where the divisibilty relation greatly obfuscates the algebraic (operational) essence of the matter - here the simple notion of a fixed point - see my answer.
$endgroup$
– Bill Dubuque
yesterday
1
1
$begingroup$
Modular arithmetic was invented to clarify proofs like this where the divisibilty relation greatly obfuscates the algebraic (operational) essence of the matter - here the simple notion of a fixed point - see my answer.
$endgroup$
– Bill Dubuque
yesterday
$begingroup$
Modular arithmetic was invented to clarify proofs like this where the divisibilty relation greatly obfuscates the algebraic (operational) essence of the matter - here the simple notion of a fixed point - see my answer.
$endgroup$
– Bill Dubuque
yesterday
add a comment |
$begingroup$
$bmod P(x)!-!x!:, color{#c00}{P(x)equiv x},Rightarrow, P(P(color{#c00}{P(x)}))equiv P(P(color{#c00}{x)}))equiv P(x)equiv x$
Remark $ $ The proof is a special case of: fixed points stay fixed on iteration by induction,
namely: $, $ if $ color{#c00}{f(x) = x} $ then $, {f^{large n}(x) = x},Rightarrow, f^{large n+1}(x) = f^n(color{#c00}{f(x)})=f^n(color{#c00}x)=x$
Corollary $ P(x)!-!x,$ divides $, P^n(x)!-!x,$ for all $,ninBbb N,,$ and all polynomials $,P(x)$
$endgroup$
add a comment |
$begingroup$
$bmod P(x)!-!x!:, color{#c00}{P(x)equiv x},Rightarrow, P(P(color{#c00}{P(x)}))equiv P(P(color{#c00}{x)}))equiv P(x)equiv x$
Remark $ $ The proof is a special case of: fixed points stay fixed on iteration by induction,
namely: $, $ if $ color{#c00}{f(x) = x} $ then $, {f^{large n}(x) = x},Rightarrow, f^{large n+1}(x) = f^n(color{#c00}{f(x)})=f^n(color{#c00}x)=x$
Corollary $ P(x)!-!x,$ divides $, P^n(x)!-!x,$ for all $,ninBbb N,,$ and all polynomials $,P(x)$
$endgroup$
add a comment |
$begingroup$
$bmod P(x)!-!x!:, color{#c00}{P(x)equiv x},Rightarrow, P(P(color{#c00}{P(x)}))equiv P(P(color{#c00}{x)}))equiv P(x)equiv x$
Remark $ $ The proof is a special case of: fixed points stay fixed on iteration by induction,
namely: $, $ if $ color{#c00}{f(x) = x} $ then $, {f^{large n}(x) = x},Rightarrow, f^{large n+1}(x) = f^n(color{#c00}{f(x)})=f^n(color{#c00}x)=x$
Corollary $ P(x)!-!x,$ divides $, P^n(x)!-!x,$ for all $,ninBbb N,,$ and all polynomials $,P(x)$
$endgroup$
$bmod P(x)!-!x!:, color{#c00}{P(x)equiv x},Rightarrow, P(P(color{#c00}{P(x)}))equiv P(P(color{#c00}{x)}))equiv P(x)equiv x$
Remark $ $ The proof is a special case of: fixed points stay fixed on iteration by induction,
namely: $, $ if $ color{#c00}{f(x) = x} $ then $, {f^{large n}(x) = x},Rightarrow, f^{large n+1}(x) = f^n(color{#c00}{f(x)})=f^n(color{#c00}x)=x$
Corollary $ P(x)!-!x,$ divides $, P^n(x)!-!x,$ for all $,ninBbb N,,$ and all polynomials $,P(x)$
edited yesterday
answered yesterday
Bill DubuqueBill Dubuque
214k29196655
214k29196655
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