### Intervals:

The intervals on a graph that are going up when reading the graph from left to right are**increasing**. The ball is pink over the increasing intervals on the graph. The intervals on the graph that are going down when reading the graph from left to right are

**decreasing**.The ball is blue over the decreasing intervals on the graph.

### Writing up intervals

Once you've identified the interval, you need the x axis value on the left for the first value. On that side, head straight up or down to the ** X AXIS ** value. If it runs off towards negative infinity on the left side of the interval, use - ∞. Then identify where it ends on the right side, and head straight up or down to the ** X AXIS** value. If it runs off towards infinity on the right side, use ∞. Put both values in parentheses seperated by a comma. If there is more than one interval, put a U in between them.

Decreasing interval is (- ∞, -2). Increasing interval is (-2, ∞). | Decreasing interval:(-2,2). Increasing intervals:(- ∞, -2) U (2, ∞). |