Points Inflection Concavity
1. **Problem Statement:** We are given the graph of the derivative function $f'$ of some function $f$. We need to find:
- (a) The $x$-values where $f$ has points of inflection.
- (b) The intervals where $f$ is concave down.
2. **Recall the concepts:**
- Points of inflection of $f$ occur where $f''(x)$ changes sign, equivalently where $f'(x)$ has local maxima or minima (critical points).
- $f$ is concave down where $f''(x) < 0$, which means $f'(x)$ is decreasing on those intervals.
3. **Analyze the graph of $f'$:**
- $f'$ has a local maximum near $x \approx -0.2$.
- $f'$ has a local minimum near $x \approx 3$.
4. **Answers:**
- (a) Points of inflection of $f$ occur where $f'$ has local maxima or minima, so
$$ x = -0.2, 3 $$
- (b) $f$ is concave down where $f'$ is decreasing.
Observing $f'$, it decreases between:
$$ (-0.2, 3) $$
5. **Summary:**
- (a) Points of inflection at $x = -0.2$ and $x = 3$.
- (b) $f$ is concave down on the interval $( -0.2, 3 )$.