Question Number 132194 by aurpeyz last updated on 12/Feb/21
Commented by mr W last updated on 12/Feb/21
$$\frac{{d}\theta}{{dr}}=\mathrm{3}{r}^{\mathrm{2}} −\mathrm{1} \\ $$$$\Delta\theta\approx\left(\mathrm{3}{r}^{\mathrm{2}} −\mathrm{1}\right)\Delta{r}=\left(\mathrm{3}×\mathrm{1}^{\mathrm{2}} −\mathrm{1}\right)×\mathrm{0}.\mathrm{05}=\mathrm{0}.\mathrm{1} \\ $$