Function Curve Analysis 134520
1. **Problem Statement:** We analyze the function $f$ defined on the interval $[1,5]$ with the given curve characteristics.
2. **Given Information:**
- The curve has two local maxima and one local minimum between them.
- The function starts near the x-axis at $x=1$ and returns near the x-axis at $x=5$.
3. **Key Concepts:**
- **Critical points** occur where $f'(x)=0$ or $f'(x)$ is undefined; these correspond to local maxima, minima, or saddle points.
- **Inflection points** occur where the concavity changes, i.e., where $f''(x)=0$ and the sign of $f''(x)$ changes.
- **Absolute maximum** is the highest value of $f$ on the interval.
- **Convex upward** means $f''(x)>0$ on the interval.
4. **Analyzing the curve:**
- The curve has two peaks (local maxima) and one valley (local minimum), so there are three critical points.
- The concavity changes twice (from convex to concave or vice versa) indicating two inflection points.
- The highest peak is an absolute maximum value on $[1,5]$.
- The curve is not convex upward on the entire open interval $(1,5)$ because it has both concave upward and concave downward parts.
5. **Conclusion:**
- (a) True: three critical points.
- (b) True: two inflection points.
- (c) True: absolute maximum exists.
- (d) False: the curve is not convex upward on the entire interval $(1,5)$.
**Final answer:** The statement (d) is not correct.