Position ○｜appendage｜___｜20260628174208-01-•

Radius vector $\vec{r}$ represents the position of a point $\mathrm{P}(x,y,z)$ with respect to origin O. In Cartesian coordinate system $\vec{r}=x{\hat{e}}_x+y{\hat{e}}_y+z{\hat{e}}_z.$

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