Answer
$1 \lt x \lt 2.5$ and for $x \gt 3.5$.
Work Step by Step
The derivative (that is, the slope of the tangent line) is positive when the height of the graph increases as we
move to the right. From the given figure, this appears to be true for $1 \lt x \lt 2.5$ and for $x \gt 3.5$.
