Question Number 64456 by ner0i last updated on 18/Jul/19
Commented by Tony Lin last updated on 18/Jul/19
$$\overset{\rightharpoonup} {{r}}'\left({t}\right)=\hat {{i}}−\frac{\mathrm{2}}{{t}^{\mathrm{2}} }\hat {{j}}−\frac{\mathrm{1}}{{t}^{\mathrm{2}} }\hat {{k}} \\ $$$$\overset{\rightharpoonup} {{r}}''\left({t}\right)=\frac{\mathrm{4}}{{t}^{\mathrm{3}} }\hat {{j}}−\frac{\mathrm{2}}{{t}^{\mathrm{3}} }\hat {{k}} \\ $$