If Pierre is going downhill, then the graph is decreasing:
So, our graph is decreasing on
Notice that I'm not using the endpoints on these:
Think about it... When Pierre is standing right ON x = -3 ...
he's not going uphill or downhill. He's just standing there!
|What if Pierre is walking on||?|
That line is horizontal (slope of 0). He's not going uphill or downhill, so the graph is not increasing or decreasing there.
For the following graph, list the intervals where the graph is increasing and decreasing:
*Remember to answer in interval notation using only x values (no y values allowed)!