Mathematics

Problem

Let

P(2,-1,4)

be a point in space. a. (a) Write its position vector

\mathbf{r}

. b. (b) Calculate

|\mathbf{r}|

. c. (c) Determine the direction cosines of

\mathbf{r}

. d. (d) Hence, write the unit vector along

\mathbf{r}