Function Intervals
1. **Problem Statement:** Given the graph of a function $f$ from $x=0$ to $x=6$, determine the intervals where $f$ is increasing, decreasing, concave upward, concave downward, and find the inflection points.
2. **Key Concepts:**
- A function is **increasing** where its slope (derivative) is positive.
- It is **decreasing** where its slope is negative.
- The function is **concave upward** where its second derivative is positive (graph curves upward).
- It is **concave downward** where its second derivative is negative (graph curves downward).
- **Inflection points** occur where the concavity changes, i.e., where the second derivative changes sign.
3. **Analyzing the graph:**
- From $x=0$ to $x=1$, $f$ increases sharply (slope positive).
- From $x=1$ to $x=3$, $f$ decreases (slope negative).
- From $x=3$ to $x=6$, $f$ increases gradually (slope positive).
4. **Intervals of increase and decrease:**
- Increasing: $(0,1)$ and $(3,6)$
- Decreasing: $(1,3)$
5. **Concavity:**
- From $x=0$ to about $x=2$, the graph curves upward (concave up).
- From about $x=2$ to $x=4$, the graph curves downward (concave down).
- From about $x=4$ to $x=6$, the graph curves upward again (concave up).
6. **Intervals of concavity:**
- Concave upward: $(0,2)$ and $(4,6)$
- Concave downward: $(2,4)$
7. **Inflection points:**
- At $x=2$, concavity changes from up to down.
- At $x=4$, concavity changes from down to up.
8. **Coordinates of inflection points:**
- Approximate $f(2)$ and $f(4)$ from the graph:
- $f(2) \approx 2$
- $f(4) \approx 3$
**Final answers:**
(a) Increasing on $(0,1) \cup (3,6)$
(b) Decreasing on $(1,3)$
(c) Concave upward on $(0,2) \cup (4,6)$
(d) Concave downward on $(2,4)$
(e) Inflection points at $(2,2)$ and $(4,3)$