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Question Number 24612 by rish@bh last updated on 22/Nov/17
![If f(x) = [x] then is fof(x) = f(x)?](Q24612.png)
$$\mathrm{If}\:{f}\left({x}\right)\:=\:\left[{x}\right]\:{then}\:{is}\:{fof}\left({x}\right)\:=\:{f}\left({x}\right)? \\ $$$$ \\ $$
Answered by jota last updated on 22/Nov/17
![Yes. [x]>= 0 ⇒ [[x]]=[x]](Q24616.png)
$${Yes}.\:\left[{x}\right]>=\:\mathrm{0}\:\Rightarrow\:\left[\left[{x}\right]\right]=\left[{x}\right] \\ $$
Commented by rish@bh last updated on 22/Nov/17
$$\mathrm{Thanks}! \\ $$
Commented by kaivan.ahmadi last updated on 13/Dec/17
![if x∈R⇒fof(x)=f([x])=[[x]]=[x]=f(x)](Q25692.png)
$$\mathrm{if}\:\mathrm{x}\in\mathrm{R}\Rightarrow\mathrm{fof}\left(\mathrm{x}\right)=\mathrm{f}\left(\left[\mathrm{x}\right]\right)=\left[\left[\mathrm{x}\right]\right]=\left[\mathrm{x}\right]=\mathrm{f}\left(\mathrm{x}\right) \\ $$