Question Number 159917 by PengagumRahasiamu last updated on 22/Nov/21
Commented by mr W last updated on 22/Nov/21
$${d}\lfloor{x}\rfloor=\mathrm{0}{dx} \\ $$$$\Rightarrow\int_{{a}} ^{{b}} {f}\left({x}\right){d}\lfloor{x}\rfloor=\int_{{a}} ^{{b}} {f}\left({x}\right)×\mathrm{0}{dx}=\int_{{a}} ^{{b}} \mathrm{0}{dx}=\mathrm{0} \\ $$