## Calculus: Early Transcendentals 8th Edition

a. Right: $0 \lt t \lt 1$ and $4\lt t \lt 6$; left: $2 \lt t \lt 3$; Still: $1 \lt t \lt 2$ and $3 \lt t \lt 4$. b. Graph
By examining the graph underneath. When the particle is moving to the right, the distance of $s$ increases. So the particle moves to the right when $0 \lt t \lt 1$ and $4\lt t \lt 6$. When the particle moves to the left, the distance $s$ decreases. So the particle moves to the left when $2 \lt t \lt 3$. When the particle stays still, there is no change in the distance of $s$. So the particle stays still in $1 \lt t \lt 2$ and $3 \lt t \lt 4$