Question Number 130139 by mathmax by abdo last updated on 22/Jan/21
$$\mathrm{solve}\:\mathrm{for}\:\mathrm{f}\:\:\:\mathrm{f}\left(\mathrm{x}+\frac{\mathrm{1}}{\mathrm{x}}\right)−\mathrm{f}\left(\mathrm{x}−\frac{\mathrm{1}}{\mathrm{x}}\right)=\mathrm{x}^{\mathrm{3}} \\ $$