Question Number 55909 by gunawan last updated on 06/Mar/19
$$\mathrm{If}\:{E}=\left\{{f}\:\mid{f}\::\:\mathbb{R}\rightarrow\mathbb{R}\:\mathrm{continoues}\:\mathrm{function}\right. \\ $$$$\left.{f}\left({x}\right)\:\in\mathrm{Q},\:\forall{x}\:\in\mathbb{R}\right\}\:\mathrm{then}\:{E}=… \\ $$