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if-fof-x-f-x-x-and-f-1-1-find-fofofofofofofofofof-1-




Question Number 208370 by lmcp1203 last updated on 14/Jun/24
if   (fof)(x)=f(x)+x  and f(1)=1     find  fofofofofofofofofof(1)
$${if}\:\:\:\left({fof}\right)\left({x}\right)={f}\left({x}\right)+{x}\:\:{and}\:{f}\left(\mathrm{1}\right)=\mathrm{1}\:\:\: \\ $$$${find}\:\:{fofofofofofofofofof}\left(\mathrm{1}\right) \\ $$
Commented by A5T last updated on 14/Jun/24
f(f(x))=f(x)+x⇒ f(f(1))=f(1)+1  ⇒f(1)=f(1)+1⇒1=^? 0
$${f}\left({f}\left({x}\right)\right)={f}\left({x}\right)+{x}\Rightarrow\:{f}\left({f}\left(\mathrm{1}\right)\right)={f}\left(\mathrm{1}\right)+\mathrm{1} \\ $$$$\Rightarrow{f}\left(\mathrm{1}\right)={f}\left(\mathrm{1}\right)+\mathrm{1}\Rightarrow\mathrm{1}\overset{?} {=}\mathrm{0} \\ $$
Commented by mr W last updated on 14/Jun/24
f(x)=1=constant?
$${f}\left({x}\right)=\mathrm{1}={constant}? \\ $$
Commented by lmcp1203 last updated on 14/Jun/24
sorry. its f(1)=1
$${sorry}.\:{its}\:{f}\left(\mathrm{1}\right)=\mathrm{1} \\ $$
Answered by MM42 last updated on 14/Jun/24
★  (fof)(1)=f(f(1))=f(1)=1  ≠f(1)+1      ?!!!
$$\bigstar \\ $$$$\left({fof}\right)\left(\mathrm{1}\right)={f}\left({f}\left(\mathrm{1}\right)\right)={f}\left(\mathrm{1}\right)=\mathrm{1} \\ $$$$\neq{f}\left(\mathrm{1}\right)+\mathrm{1}\:\:\:\:\:\:?!!! \\ $$$$ \\ $$
Commented by lmcp1203 last updated on 14/Jun/24
this problem is wrong. thanks
$${this}\:{problem}\:{is}\:{wrong}.\:{thanks} \\ $$
Answered by mathzup last updated on 14/Jun/24
oooooof....
$${oooooof}…. \\ $$

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