## Calculus (3rd Edition)

$$\langle -1,5,\frac{1}{2} \rangle .$$
Since we have $$r(t)=(4-t)i+(2+5t)j+\frac{1}{2}tk$$ then we rewrite $r(t)$ as follows $$r(t)=(4,2,0)+t\langle -1,5,\frac{1}{2} \rangle .$$ Hence, the direction vector is given by $$\langle -1,5,\frac{1}{2} \rangle .$$