Exercise 13 Page 384

The ray $\overrightarrow{AE}$ has endpoint $A$ and goes through $E$ before continuing on indefinitely.

For two rays to be the same, they must have the same endpoint and point in the same direction. Therefore, we need to use $A$ as the endpoint when creating an alternative name. For the point giving the direction, we can use $C$ instead since it lies on $\overrightarrow{AE}.$ An alternative name for $\overrightarrow{AE}$ is then $\overrightarrow{AC}$ — they have the same endpoint and direction.