Question Number 83935 by Roland Mbunwe last updated on 08/Mar/20
$${If}\:\:\boldsymbol{{x}}^{\mathrm{4}} \:{and}\:{higher}\:{powers}\:{of}\:{x}\:{are}\:{neglected},\:{show}\:{that} \\ $$$$\sqrt{\left(\frac{\mathrm{1}−{x}}{\mathrm{1}+{x}+{x}^{\mathrm{2}} }\right)=\mathrm{1}−{x}+\frac{\mathrm{1}}{\mathrm{2}}{x}^{\mathrm{3}} } \\ $$