Function Curve Analysis 1F54B0
1. **Problem Statement:** We analyze the function $f$ defined on the interval $[1,5]$ and determine which of the given statements (a) to (d) about its critical points, inflection points, absolute maximum, and convexity are correct or not.
2. **Definitions and Formulas:**
- A **critical point** occurs where the first derivative $f'(x) = 0$ or is undefined.
- An **inflection point** occurs where the second derivative $f''(x) = 0$ and the concavity changes.
- An **absolute maximum** is the highest value of $f(x)$ on the interval.
- The function is **convex upward** (concave up) where $f''(x) > 0$.
3. **Given Information from the Graph:**
- Critical points approximately at $x=1.5$, $x=3$, and $x=4.5$ (3 points).
- Inflection points approximately at $x=2$ and $x=4$ (2 points).
- The highest peak near $x=4$ suggests an absolute maximum.
- The curve changes concavity at inflection points, so convexity varies.
4. **Check Each Statement:**
(a) "The function $f$ has three critical points."
- From the graph, there are 3 critical points at $x=1.5$, $3$, and $4.5$.
- So, (a) is **correct**.
(b) "The function $f$ has two inflection points."
- The graph shows two inflection points at $x=2$ and $x=4$.
- So, (b) is **correct**.
(c) "The function $f$ has an absolute maximum value."
- The highest peak near $x=4$ is the absolute maximum on $[1,5]$.
- So, (c) is **correct**.
(d) "The curve of the function $f$ is convex upward on the interval $]1,5[$."
- The function changes concavity at inflection points, so it is not convex upward on the entire interval $]1,5[$.
- It is convex upward only on subintervals where $f''(x) > 0$, not the whole interval.
- So, (d) is **not correct**.
**Final answer:** The statement that is not correct is (d).