1. These are intervals where the graph is above the x-axis, hence positive.
2. These are intervals where the graph is below the x-axis, hence negative.
3. The first interval is between the left peak and the valley, where the graph is decreasing. The second interval is right of the right peak, where the graph is also decreasing.
4. The first interval is left of the left peak, where the graph is increasing. The second interval is between the valley and the right peak, where the graph is also increasing.
