(731, #13) Sketch the curve with the vector equation

(731, #13) Sketch the curve with the vector equation .
Indicate with an arrow the direction in which t increases.
Solution: When t is less than 0 the x, y, and z coordinates are all decreasing functions of t, so the vector is moving down the curve toward the origin. When t is greater than 0 the coordinates are increasing functions of t, and the vector is moving up the curve.

Maple code

by: gm